What pokémon got affected most by changes in the remakes of their games?

[MoonlightRose]

Apologies for the probably confusing title but I couldn't think of a better way to word it.

Changes like the physical/special split, moves being changed in how they work such as Dig going from 100 power in Red and Blue to 60 in the remakes and changes to learnsets can affect how well a pokémon does in the original version of a game compared to its remake, but what pokémon has been affected the most?

I don't know if it's the most affected, but the yellow mouse is certainly hurt by the changes in BDSP. There wasn't much reason to use him in Diamond and Pearl in the first place, the lack of the Solaceon Runis Thunder Stone meaning his only upsides were the Light Ball, Grass Knot and natural Thunderbolt, which was debatably enough when the competition was Luxio and Pachirisu. In BDSP, where the Magnemite and depending on verson Elekid lines are available and Thunderbolt can be bought there's pretty much no reason to use the series mascot over other, better electric types.

 

[QuentinQuonce]

Off the top of my head:

• Surskit is borderline impossible to find pre-Norman in the original RSE and quite underwhelming if you somehow do manage to get one since it doesn't have the best learnset, but I caught a bunch of them with the DexNav in ORAS and ended up getting one with Hydro Pump, and it became a one-mon wrecking crew. Obviously many Pokemon benefit from being able to acquire egg moves in the wild, but Surskit is a much more notable case since it's literally a 1% encounter on Route 102 in the original games.
• Charmander is way, way better in FRLG than it is in RBY, partly thanks to Fire Pokemon just generally becoming better since Gen I but mostly since it gets Metal Claw. It can actually take on Brock's Geodude and Onix and take care of wild Geodude in Mt Moon. One small addition to its movepool makes it miles better than it would otherwise be; Charmander is often thought of as the least useful starter in the earlygame but this makes it as good as Bulbasaur and Squirtle from the off.
• Conversely, Cyndaquil becomes a little worse in HGSS since it loses a lot of useful moves it had access to during Johto. I've soloed Johto with Typhlosion many times - it gets a decent array of options and it's very easy to fill four moveslots. But it loses Thunderpunch, Dynamicpunch, and Mud-Slap (and, uh... Fury Cutter) and doesn't get a whole lot back. Focus Punch isn't great in-game, Solarbeam and Brick Break come too late, and Aerial Ace and Rock Tomb have redundant coverage. It gets Shadow Claw but can't learn it until its final stage, which is likely too late for the main boss it's good against (Morty). At least it still has Headbutt and Hidden Power!
• Abra also forfeits a bit of its star power from GSC to HGSS thanks to the loss of the elemental punches. It's still good, of course, but it's left with Focus Blast as its only accessible coverage move until the player beats Morty and can get Shadow Ball and Charge Beam (unless one gets lucky and manages to get Charge Beam in the Dept Store Lottery).

 

[Hugin]

Yellow was big for this. Mankey and both Nidorans became much more viable anti-Brock options, encouraging you to add them to your team. Plenty of other mons got shifted heavily by very minor fixes.

Feraligatr was hurt by the swap to HGSS. It's not bad, but the Physical/Special split and changes to coverage made it notably less incredible.

Gyarados is one that changes heavily based on the details of the game it's in, including remakes. Phys/Special split, Intimidate, coverage TMs, how grinding works...It can be a lead weight you have to really work with until it sweeps the E4, or it can just involve a bit of grinding and suddenly tank everything and OHKO bosses. I'd rather not go through individual examples, but it's big changes every version.

 

[pika pal]

Sceptile made significant gains in my book going from Gen 3 to Gen 6 versions of Hoenn. The most obvious would be its access to its Mega, but another thing I can cite immediately is the infinite/updated TMs in the remakes, Energy Ball in the Safari Zone being a much stronger main STAB move to give it than Gen 3's unbuffed Giga Drain, plus TMs no longer being a contested resource if you want to give it something like Earthquake or buy Focus Blast to deal with Steel Type match-ups.

This might be a bit of a stretch, but I think the Nidos took a slight hit between RBY and FRLG, mainly with the TM shifts since they lean so heavily on those for their Gen 1 sweep potential. A lot of the "Elemental Staple" TMs in Gen 1 were awarded through simple progression or pretty accessible means: Thunderbolt was from beating Lt. Surge, Ice beam could be bought at the Celadon Department Store, and Earthquake was just lying in Silph Co. So you could get most of their best moves accessible before you fought 4-5 of the Gym Leaders, and several of those Coverage options were pretty useful for said battles. In FRLG, a lot of the moves got moved to either later obtained (EQ becoming Giovanni's prize) or put behind less accessible means likee the Rocket Game Corner. This combined with the EV/Nature system means a potentially weaker Nido working with less optimal moves for more of the game (if you even buy into the Game Corner TMs for them).

I don't think it's anything quite as dramatic as GSC -> HGSS for Cyndaquil, but it springs to mind considering Yellow made them a lot more notable with Double Kick for Brock and not having the Starters to compete with for Elemental Juggernauts (so pulling a lot more weight in Mt. Moon and some Cerulean City battles.

 

[Esserise]

This is more of a niche role, but Cubone became considerably less useful at Lavender Tower due to the Gastly line picking up Levitate in FRLG. (The pendulum swung back for LGPE, though.)

 

[ceal]

• Basically any Dark type in Hoenn gained a lot from being able to use their STABs in conjunction with their higher Attack stats.
• I disagree that Cyndaquil got worse in HGSS. Sure, it lost Thunder Punch late-game but gained better items between improved Charcoal and Choice Specs, and Fire Blast via the department store, letting it put out some ridiculous damage, even 2hkoing Miltank, allowing it to better contribute in fights without using up a bunch of niche TMs for the purpose of tackling a single mu.
• Sandshrew and Diglett losing their ability to auto-crit with Slash and a strong Ground STAB in Dig/earlier EQ basically toileted their viability.
• Mawile went from bottom of the barrel to almost broken thanks to its Mega.
• Geodude was fine already in GSC but Rock Polish alone made it so much better in HGSS.

 

[Roldski32]

Cyndaquil losing Thunderpunch in HGSS isn't that big of a deal, and even in GSC, it only hits like 3 targets (Rival's Feraligatr, Will's Slowbro, Lance's Gyarados). Not to mentioned, you can't even used it right away until Level 36. Thunderpunch is now a physical move in HGSS, which uses its 84 Atk instead of 109 SpA unlike in GSC, Gyarados has Intimidate and I largely doubt you can even one shot-it, It hits Slowbro's high 110 Def instead of lower 80 SpD, and as for Rival's Feraligatr, it gets cleanly 2HKOed by Choice Specs Fire Blast into a Blaze-boosted one.

 

[MegaFlareon]

--->

The type chart changes between Gen 1 and Gen 2 gave Beedrill a hit in viability in FRLG. Beedrill is notable in Gen 1 for actually having the best Bug attacks in Twineedle and Pin Missile (lol). Back in RB, Poison was weak to Bug so Beedrill can easily sweep Erika and many route trainers as Grass/Poison Pokémon have double weakness to Bug. In addition, Beedrill could also hit many of Team Rocket's Pokémon super-effectively.

In FRLG, the Grass/Poison Pokémon are now neutral to Bug, while many of Team Rocket's Pokémon now resist Bug. Scyther, which has way better stats, now also has gained Silver Wind so Beedrill doesn't have the best Bug attacks in this game either.

Thankfully, Beedrill rebounded quite well in the Let's Go games thanks to a powerful Mega Evolution!

 

[khlaylav]

It's not that Gyarados or Feraligatr were bad per se in Gold and Silver, but the physical/special split really benefitted them both in Heart Gold and Soul Silver. They even picked up useful coverage in Ice Fang, though Feraligatr had to wait much longer for Aqua Tail than Gyarados.

In contrast, Typhlosion, Alakazam and Ampharos suffered for the loss of the elemental punches. Alakazam could still function fine because... well... it's freakin Alakazam, but Ampharos and Typhlosion both had to suffer with lower accuracy Thunder and Fire Blast

Come to think of it, Houndour and Houndoom actually suffered a bit from the physical special split because Bite was a strong STAB move.

Finally, earlier accessibility and the physical special split made Misdreavus much more usable than in Gold and Silver. Heck, Charge Beam let it get Special Attack boosts and was useful coverage along with Psybeam.

 

[QuentinQuonce]

--->

The type chart changes between Gen 1 and Gen 2 gave Beedrill a hit in viability in FRLG. Beedrill is notable in Gen 1 for actually having the best Bug attacks in Twineedle and Pin Missile (lol). Back in RB, Poison was weak to Bug so Beedrill can easily sweep Erika and many route trainers as Grass/Poison Pokémon have double weakness to Bug. In addition, Beedrill could also hit many of Team Rocket's Pokémon super-effectively.

In FRLG, the Grass/Poison Pokémon are now neutral to Bug, while many of Team Rocket's Pokémon now resist Bug. Scyther, which has way better stats, now also has gained Silver Wind so Beedrill doesn't have the best Bug attacks in this game either.

Thankfully, Beedrill rebounded quite well in the Let's Go games thanks to a powerful Mega Evolution!

Oh I loved Beedrill in FRLG. Taught mine Giga Drain and it was such a monster. My squad for my first-ever playthrough of FRLG was like a "who's who" of crapmons (except for Blastoise): Beedrill, Primeape, Farfetch'd, Wigglytuff... can't remember if there was a fifth. Happy days.

Gyarados has Intimidate and I largely doubt you can even one shot-it, It hits Slowbro's high 110 Def instead of lower 80 SpD, and as for Rival's Feraligatr, it gets cleanly 2HKOed by Choice Specs Fire Blast into a Blaze-boosted one.

...all of this points to why Thunderpunch is a good option in GSC, though. It's a worse option for Typhlosion in HGSS but it'd still be a useful move to have nonetheless. Having a reliable move to hit Waters is great (and rare pre-Gen V) for anything Fire-typed.

Also I think people are way over-egging what I said re Cyndaquil, from the replies you'd think I said it was utterly useless in HGSS. When my actual words were

a little worse

 

[khlaylav]

Zubat in general gains a lot from the remakes, especially when considering HG/SS and OR/AS. In gens 2 and 3, Zubat is at best functional even with the evolution into Crobat; I mean it learns Wing Attack at Level 27 in Gold and Silver, for god's sake. Gen 3 pushes that down to 21, still an insane amount of time to wait for a reasonable STAB. It isn't until Gen 4 that Wing Attack becomes a much more manageable 17, and Poison Fang, while not good, gets pushed down to 33 from Gen 3's 41; still unreasonable but at least earlier (all these are using only Zubat, by the way).

I'd say Zubat gains the most in Gen 6. Acrobatics by level up is nasty and even then, Wing Attack at level 13 lets you clown Brawly. In addition, its surprisingly robust TM and tutor move pool gives you some nice options. Poison Fang at 27 gives you a second physical STAB and then you can reteach Cross Poison and clown on Fairy types, including the Ralts line, which is fun.

 

[bdt2002]

At first glance, it may not look like Treecko and its evolutions improved that much compared to their appearance in the original Hoenn games. It also doesn’t appreciate the Champion being Steven again if you’re comparing ORAS to Emerald specifically. However, the improvements to their movepool help alleviate one of Sceptile’s biggest weaknesses from the originals, those being that some of its best moves have low Base Power. Leaf Blade is the main one that got buffed, of course, but there’s a handful of other ones I can think of too, like the early-game TM for Bullet Seed for example. Sceptile also gained access to Dual Chop in the remakes, giving it access to a move comparable to Dragon Claw (albeit with 90% accuracy instead of 100%) when you account for both hits being 40 Base Power a piece.



Upon further inspection, I’ve found that the fourth generation games were surprisingly brutal to the Abra family. In the first three generations, Abra could compete with the best in the game- in GSC, even being considered the best Pokémon on the most recent Viability Rankings thread- and while Abra can still perform in both DPP and HGSS runs, it’s not the game-breaking monster it used to be. In HGSS in particular it doesn’t enjoy losing the special-oriented elemental punches that made Abra’s family such a threat in GSC, and it also doesn’t enjoy having to rely on the inconsistent Focus Blast for type coverage, hit as hard as it might. The real problem for Abra’s family comes in Sinnoh, in both its original games and BDSP; Dark and Steel-Types started to become a lot more common during the main campaign in Sinnoh, especially in Platinum, and in later Sinnoh installments it faces competition for a team slot with Pokémon like Espeon, Gardevoir, Gallade, and Mr. Mime to name a few.

 

[ScraftyIsTheBest]

If anything Cyndaquil actually got better in HGSS compared to GSC. It may not have the same style of play that it did in the originals, but HGSS Typhlosion is arguably overall more effective. GSC Typhlosion has good coverage thanks to Thunder Punch and EQ, but it's held back by its poorly spread out distribution of Fire STAB over the course of the game. It's stuck with the weak 40 BP Ember for far too long, has to wait until Level 31 for Flame Wheel, needs to rely on Fire Punch for slightly stronger Fire STAB, and doesn't learn Flamethrower until Level 60 iirc.

Meanwhile in HGSS in addition to getting the Fire Blast TM early, Quilava also learns Flame Wheel earlier (which while now physical, still delivers more of a blow coming from Quilava with a passable Attack for that point of the game), learns Lava Plume, an 80 BP Special Fire move with a high burn chance, at Level 35, and Flamethrower much earlier at Level 42. The latter being notable as it now has a strong Fire STAB in time for the Elite Four Round 1. But the main catch is that around the time you get Surf, you can get the Choice Specs, which in tandem with Typhlosion getting stronger Fire STAB like Fire Blast and Flamethrower earlier, allows Typhlosion to muscle past its opponents more effectively using raw power. It may not have the same magnitude of coverage, but it has more raw power at its disposal. The introduction of abilities is also a boon for Typhlosion, especially since it has the usual Blaze that Fire starters have, meaning a Typhlosion at low HP with Choice Specs, Blaze-boosted Flamethrower/Fire Blast can hit brutally hard. Its main "coverage" options are stuff like Focus Blast, Solar Beam (it has this now too!), and to an extent Hyper Beam, but that's still workable and frankly if you want you can also run a Sunny Day+Solar Beam Typhlosion which also has sun boosted Fire STAB to work with.

In GSC Cyndaquil as a whole is actually rather mediocre, but in HGSS it's genuinely an overall solid starter and can be a strong Pokemon on par with Feraligatr for an in-game run (in GSC Feraligatr>>>>>both Typhlosion and Meganium). It just functions a lot differently in HGSS, focusing more on sheer power behind its special attacks rather than a colorful range of coverage like in GSC.

 

[Ernesto]

The Abra family has been mentioned a couple of times as suffering in the transition to newer gens, however I'd say Kadabra in particular suffers the most.
In the first games it was basically Zam but slower (and frailer) which meant it was still destroying most stuff. In gen 3 it started to lose ground both because it doesn't learn Calm Mind by level-up unlike Zam and the increased number of Dark-types, but particularly in the fourth gen it got hit hard by not being able to learn Focus Blast. I remember playing Diamond on an emulator and having caught a Modest Abra with Hidden Power Fighting (with something like 59 BP) that rolled over stuff early game, but since I couldn't trade I was forced to keep using HP Fighting into the E4. Needless to say it barely got any OHKOs even with Choice Specs and died to a slight breeze.

 

[mertyville]

->
Besides getting Metal Claw, lv32 Flamethrower as Charmeleon really boosted the usefulness of the Charmander-line. It is really fun to use. I think generally Fire Types got a lot better from the transition. Also Blaze is a neat ability as the weaker you get, the harder your fire moves hit. Last time I checked, Mega Kick was 120 Base Power Normal Type move in Gen 3 which you probably want to teach it after Mount Moon giving you some advantage against Misty.

->
Moltres got a few benefits for in-game use. It is slidely earlier to obtain. Sure, it won't be more effective since you can only additionally use it for Giovanni, but you get STAB Flamethrower. I think that is a huge enough of an improvement worth mentioning.
->
Sadly Chikorita didn't get so lucky. It can hit harder thanks to Overgrowth but being unable to max out all your stats hurt since it won't be nearly as tanky or hit hard enough. Physical Razor Leaf is also a bummer. Not such a big deal but still hurts.

->
I think Ho-oh was already a fantastic Pokemon in Gen 2, but all the buffs around in Gen 4 really elevated Ho-oh to another level:
- Sacred Fire is Physical
- Brave Bird
- Early Ancient Power
- Lv45 encounter instead of Lv40
- Punishment as an alternative tech against Psychic Types

 

[Ramblin Wreck]

Gyarados gaining Intimidate, physical water moves, and Dragon Dance are all major boosts from GSC to HGSS. Sneasel got physical STAB and an evolution to play with. Tyranitar could run dual STABs without having to be a mixed set, got Sand Stream, and then got the 50% SpDef boost on top of that. Gengar swapped out a ground weakness for an immunity and got special STAB.

 

[QuentinQuonce]

In addition to others mentioned, a vast amount of Kanto Pokemon improved from RBY>FRLG; some a little, some a lot. In most cases this was simply due to finally being able to access STAB moves.

• Omanyte and Kabuto both get Rock-type moves without breeding or events! Good for them. Doesn't do much to improve their viability in-game, but both are also much more capable than they were before thanks to their abilities.
• Scyther is marginally better thanks to getting Wing Attack at a decent level now, as well as Aerial Ace by TM if for whatever reason Wing Attack isn't your bag. Sadly it still doesn't get a Bug move without tutoring or breeding unless you're willing to wait until level 46 for... Fury Cutter (literally why). Having an evolution helps in theory, though of course it's locked to the postgame and needs a trade to accomplish.
• Pinsir is in a similar boat; it still doesn't get any STAB moves at all, but learns by level much better moves this time around: Revenge, Brick Break, Submission. And thanks to gaining access to Earthquake and Rock Slide (and a couple of Dark moves if you really want) it can put together a moveset that doesn't solely consist of Normal and Fighting moves. Ironically, it does lose Slash which was by far its best level-up move in RBY.
• The Dratini line was already pretty stellar but getting actual Dragon moves to play with is nice even if it's not essential
• Sandslash's level-up movepool is still terrible, but it gets access to a slightly wider array of TM and tutor moves than it did before - Aerial Ace, Iron Tail, Thief, and of course Hidden Power. While it's not that improved overall, it does at least mean that it's not competing quite so hard for TMs with other Pokemon, which is a common issue when playing through RBY with a full team of six.
• Rhyhorn and Rhydon are sort of the opposite case: they already had very wide movepools with the aid of TMs in Gen I, but finally getting some STAB by level is a boon in a game where most TM and tutor moves are still one-use. It's not a total fix, because Rhyhorn still doesn't learn Earthquake until level 52 and it's unpleasant to forgo evolution for that long, but Rock Blast is a decent enough move to get by on if you're using it in-game and don't teach it anything else.
• Cubone lost the ability to hit Gastly with Ground-moves, but it gained the Thick Club in return. Admittedly the odds of catching a Cubone with a Thick Club in FRLG are astoundingly poor, but few Pokemon are that improved by a held item. Compare it against other Pokemon with dedicated held items like Ditto and Chansey - Thick Club on Marowak is almost mandatory.
• Conversely, pretty much all the birds (Pidgeot, Dodrio, Fearow et al) got very slightly better thanks to now being able to learn moves not solely of their STAB. Steel Wing (or Hidden Power Steel or Fighting) probably still isn't winning you very many matchups against Rock-types but hey.

Another HGSS example:

Some might quibble whether it could ever really "improve", but Shuckle's movepool is so much more expansive in Gen IV than it was in II. It's far more capable as a disruptive staller thanks to getting moves like Knock Off, Stealth Rock, and Gastro Acid. The only real loss to its movepool was Curse, but Shuckle is hardly a phenomenal Curse sweeper. The best Shuckle could really hope to do in Gen II was Toxic-trapping or PP stalling and it's still capable of that two generations later, but why would you when scandalising your enemies with Power Trick is so much more fun?

 

[mertyville]

Continuing further
->
Gastly got Levitate making it 3 immunities and the ability to actually hit Ghost Types for Super Effective Damage from the transition of Gen 1 to Gen 3. The latter isn't that big of a deal considering the lack of Ghost being Physical and Dark Type moves are a hindrance, but overall I would say it improved in a sense. Nightshade sadly don't hit Normal Types.
->
Gen 2 to Gen 4 is a mixed bag. If you look at it from using Gengar, you lost the amazing Elemental Punches. But without Gengar, you got Levitate + STAB that is Special improving it even further than Gen 3 did.
I would also say the Shiny form is a downgrade in Gen 4 as Shiny Gastly looked significantly better in Gen 2 IMO.

 

[khlaylav]

I'd suggest Scyther got some massive gains for HeartGold/SoulSilver in game. Earlier Wing Attack (21 versus 30), Technician to boost its weaker moves, usable Bug type STAB in U-Turn and X-Scissor even if they don't benefit from Technician, and then of course Scizor gets Bullet Punch if you go that route. Heck you even get fun if not super useful coverage in Thief and Rock Smash which are both powered up.

 

[Cobalt Empoleon]

A bunch of Normal-types got worse (at least relative to everything else) between GSC and HGSS, mostly because STAB Headbutt with the Gen 2 Plain Badge boost is way more threatening than anything most other Pokemon are capable of doing through the midgame. In conjunction with physical Shadow Ball (with the Fog Badge boost) and Dig/Mud Slap, Pokemon like Furret and Raticate can clear most of the game super efficiently. In HGSS spamming Headbutt just doesn't get you as far.

 

[mertyville]

->
Psychic Types in general got obviously worse, but Abra especially I think got worse the most. It lost bulk, immunity to Ghost, the ability to Abuse the Mew Glitch, Reflect being permanent and whatnot. Getting Dark Type weakness is also not nice and it didn't get a very useful ability. The downgrade from the stats experience system and the lack of bag boosts certainly hurt all Pokemon but in terms of defense, Abra got hurt the most in my mind.


->

Mawile really got a lot from the generational transition 3 to 6. It can now hit stuff Super Effectively more likely, Fairy Typing and Iron Head. I think Mawilenite comes really early but not sure if you can pick it up at that point and you need to beat the 5th gym. While Slow and still will get hit, if you have the Mega, you get a lot of power under your belt. Anyone who played Gen 6 Mega Mawile can agree I think.
Also more physical moves are always a plus as Bite used to be special. Also more customizable with TMs unlike back then not to mention since TMs are infinite use, you don't lose buffing your other Pokemon potentially. But like always you can just slap Fire Blast until you get something more reliable.

->
I think many mentioned the lack of Elemental Punches which gave it a very amazing coverage and the stat experience system which hurt Abra the most. Also considering the addition of physical Dark Moves, there are more options to take it down. At least you got special Shadow Ball.
Also Alakazam used to learn Dig, now it can't. You can't tell me that is not a downgrade.

->
I think generally Abra got a little better from the transition from Gen 3 to 6. Obviously Dark having physical moves hurt it, but dexnav gives you access to some good Abra variation to use especially with Magic Guard (well, maybe that shouldn't be counted). Also Shadow Ball being special helped it a lot too, you can use that as coverage instead of just having Psychic Type moves for most the game.
And if I am not mistaken, unless some requirements need to be fullfilled, you get Alakazanite really early before you get your Mega Bracelet. Probably not the best mega, but having access to such a powerful Pokemon like Mega Alakazam while the power level of the enemies is mostly low is a big plus in its favor I would say. Also losing Elemental Punches in this is not a big deal. They were only in the Battle Frontier which is post game. You can consider it in-game relevant for the battle frontier, but I say it is not that big of a plus for gen 3 as you would have all the coverage you need in Gen 6 for Alakazam for its equivalent of the Battle Frontier.
->
Do I ned to even explain this? I mean sure, you still have no physical Fire Move for the extra STAB. But the extra boost in stats especially Special Attack really makes Groudon very customizable and devastating. You only have 1 weakness effectively. You gain something better than Earthquake. Groudon just hits hard especially with guarantied 3 31 ivs. Hits harder. Is bulkier. But takes a long time to transform every battle which can be annoying. But in contrast, you are not wasting any turns being reminded the sun is shining. So it does safe some seconds in animation. Spamming Eruption is fun.
I also want to mention that Kyogre did get better too, but Kyogre is so powerful, the extra buff for ingame runs is almost irrelevant. So much so that speedrunners don't even use Primal Kyogre. You probably will use Primal Kyogre because permanent Rain which is the downgrade that doesn't affect Kyogre and Groudon in this game.

 

[khlaylav]

Beautifly and Dustox are not what you'd call phenomenal. Or great, or even good really but Omega Ruby and Alpha Sapphire give them some neat toys to play with (all sourcing from Serebii):

• Beautifly got a base stat buff, to start off with: Beautifly got 10 to its Special Attack to round it up to a solid 100. Dustox got... nothing, which will likely go into the Annoying Things about Pokémon thread, but regardless.
• The physical/special split was a big buff to both. While Beautifly has a (slightly) workable 70 Attack, its best pre-existing Bug and Flying moves (Silver Wind and Air Cutter for Beautifly) getting classified as Special are a big assist. Dustox has a terrible 50 in both attacking stats to work with, but regardless as you'll see in a minute, Special attacks are far more workable. Shadow Ball getting moved to Special also helps with coverage in corner-case situations like fighting Ghosts.
• Changes to level up movesets also help. Gust and Absorb are switched around in Beautifly's movepool, being learned at 10 and 12 respectively, learning Stun Spore and Morning Sun earlier and even picking up Air Cutter at 20. Mega Drain comes in at 22 and then Silver Wind at 25, a whopping nine levels earlier than Ruby and Sapphire. You even get a buff to Giga Drain at 32, six levels earlier than Ruby and Sapphire.
• Dustox also gets some of its toys earlier than Ruby and Sapphire. Gust is learned at 12, a level earlier than the originals, and Moonlight is three levels earlier than Ruby and Sapphire, picking up new move Venoshock at 20. Psybeam at 22, Silver Wind at 25 and Toxic at 32, all earlier than Ruby and Sapphire. Interestingly there is a big nerf here; Protect is learned 37 instead of 17, likely to prevent an easy win against Norman.
• Gen 6 and beyond also give Poison types a nice buff in being super effective against Fairy types. It might not be STAB for Beautifly but it can still take advantage of Venoshock and Sludge Bomb, which I'll discuss next.
• Let's close out with the big-ticket items. Bug Buzz and Quiver Dance alone are phenomenal for any Bug type, and Beautifly and Dustox are no exception. They even learn both moves at workable levels; Bug Buzz at 35 and Quiver Dance at 40, reasonable times for both powerful moves. If you'd rather power over health regeneration, Energy Ball is a TM in the Safari Zone, again reasonable for the timing and for coverage. It's not just those strong moves, though; Venoshock and Struggle Bug are not phenomenal moves in and of themselves, but any Special attacking Bug or Poison type would kill for those in-game, and they're buyable at Mauwille and Slateport, respectively.

That's a lot on two Bug types I'm not personally high on, but they are an interesting case study for remakes and how the Bug type has improved as time goes on.

 

[Eeveeto]

Farfetch'd in RBY: Stonks!
Farfetch'd in FRLG: Not stonks (it's still decent due to boosted experience, but doesn't have 100% Slash crit anymore and also non Max EVs is pain).

 

[mertyville]

->
Transition from Gen 2 to Gen 4 is really rough for Mareep. Sure, it still has good coverage and got Static, but for an ingame run it won't help much. Stat experience system is not kind to it. There aren't many ways to raise its special attack ingame. But most importantly, Thunderpunch and Firepunch are neither TMs nor special attacks anymore. Fire + Electric coverage is so good and it is a shame Mareep can't abuse it.

->
Can you guess what happened to Articuno? It's 125 Special turned into 125 Special Defense instead of Special Attack. It has like 95 or less Special Attack (too lazy to look up). If you think that's bad, it lost 90% Blizzard and it doesn't even learn it immediately after level up. I think the enemies also have better Super Effective options against it, which is extra punishing. They also nerfed it by replacing the 65 base power BubbleBeam with 60 base power Water Pulse.
You could say "Use Mind Reader + Sheer Force" which is nice, but you are wasting 2 turns for a guaranteed kill. Not sure if that is very efficient when you could have just 1HKO with Blizzard back then.
->
Pidgey got slidly better in my mind. Sure, Gust early was replaced by the 5 point lesser Tackle, but it is now a Flying Type move which it learns at lv9... wish it was earlier. Wing Attack got buffed too and it learns it 4 levels earlier as Pidgeotto.
Meanwhile in Gen 4...
->
I think unlike from Gen 1 to 3, Pidgey got worse from 2 to 4. One factor is the physical and special split taking away the physical Gust thus weakening it. You don't get Mud Slap either which is now special too. You have reliable recovery but eh...
Most importantly, the competition of good flying types got even bigger thanks to the Safari Zone. You can get Dodrio early on.
->
I like catching Dugtrio over Diglett in the Diglett cave and it is very destructive in that point of the game just like the anime portrayed it as. You have 100 Base Power STAB Dig and high crit Slash... This thing was insane whenever I played Gen 1. But the transition to Gen 3 wasn't that kind as the critrate nerf hurt it. But most importantly: 40 base power nerf to Dig.
Yeah, you can still have it learn the same base power Earthquake, but it is not nearly as satisfying. Also because Dugtrio has so low defenses, it loses the ability to survive thanks to the stat experience being replaced by the EV system.
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Gyarados also got nerfed from the transition Gen 1 to Gen 3 in the remakes. The Special Stat Split robbed it a lot of points in Special Attack. So you don't hit as hard with Thunder, Fire Blast, Blizzard etc anymore. Blizzard nerf hurt it offensively too since it doesn't hit hard. Water is special and no Flying STAB. Hyper Beam can't skip recharge turn through finishing off the opponent. A lot of things speak against Gyarados.
Still a good Pokemon for ingame. You can use it as HM slave, Earthquake which is new to his moveset and Intimidate is useful. Other than that, Gyarados isn't very satisfying to use.
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On the other hand, in the jump from Gen 2 to 4 Gyarados got a few benefits. One being that your IVs don't determine whether you are shiny or not, so the Shiny Gyarados itself can be even stronger like a regular Gyarados. Physical Special Split gave it physical Water STAB to abuse in addition to Intimidate from earlier. It learns Ice Fang per level up too. Bite is also physical. It is not much but enough to make it enjoyable to use.

 

[Eeveeto]

^To the above guy, the Articuno part is only true if your only way of going in-game is just clicking the strongest Move. For some people that's it, but not everyone has to play the game like that.

In exchange of what it lost, Articuno in Gen 3 gained Pressure and Leftovers as item. This means that it can pull off the Sub + Protect Pressure tactic. If he is faster than the opponent (and since opponents in-game often dont have EVs, he will be) , this means Articuno wins vs almost 100% of opposing Mons by PP Stalling the moves that can break Sub. Aerodactyl is the best Mon at abussing this strategy, but Articuno has the advantage of not needing it vs Giovanni (it just OHKOs all Mons with Ice Beam) and winning faster vs Lance, Bruno's Onixes and Blue's Rhydon. Articuno also starts at level 50 vs Aerodactyl needing to be trained, so the only investment to beat the game with Articuno ends up the time needed to PP Stall, which is not much.

Sub + Protect + Pressure is a very viable strategy in Nuzlocke runs of hard Hackroms. In regular Pokemon games? It's just an autowin button.