If Crawdaunt had Water-type Ivy Cudgel instead of Crabhammer, it would not be broken and it's tier likely wouldn't even change. That alone should be sufficient evidence that the move is not intrinsically broken relative to Crabhammer.
What sufficient evidence? You are merely making an assertion that I disagree with. Crabhammer has both lower accuracy and makes contact, making it far more susceptible to hax and helmet chip. As someone who loves Craudaunt, I can tell you spamming Crabhammer is much more difficult against certain team comps because of those two factors. It's a world of difference. Most of the time it gets a free move off, Crawdaunt spams Knock Off because of the utility of getting rid of items and the risk from Crabhammer. Water type Ivy Cudgel would be a huge game changer.
I don't know if it would specifically be OP in OU since it was never an OU mon, and this is where I feel these sorts of discussions can become a bit disingenuous, but it would certainly be a lot stronger. Ivy Cudgel is >> Crabhammer.
Pyro Ball is generally better than Fire-type Ivy Cudgel because of the higher KO power, and Diamond Storm is comparable to Rock-type Ivy Cudgel. Should Pyro Ball and Diamond Storm be banned for being "intrinsically broken"?
First of all, Pyro Ball is a 90% accurate move. It's not the same. It's not as reliable. It also has no effect against the Bulletproof ability. I love building with Ace, and I can tell you I lost a ton of games off of Pyroball misses.
Diamond Storm is a better argument, except even that is 95% accurate and has a chance to miss. The 50% defense boost chance is still awesome, though. Diance is held back by its speed and typing. If it was OU level or on a better mon, we would probably be talking about it.
Ivy Cudgel is on 4 mons (or at least version of it) that, if not outright OU level, are very usable in OU. One is banned, another is maybe on the way, and then Cornerstone is highly underrated at the very least.
V-Create is not clearly worse than Fishious Rend and Bolt Beak for sheer breaking power. Fire immunities are rarer than Electric immunities or even Water immunities, and V-Create can also be stacked with weather just like Fishious Rend. Even if you have to switch out more, switching out a breaker to avoid a revenge kill is not that uncommon anyways. The point is that even if Fishious Rend can be deemed overall better, it is not so far above and beyond other powerful moves that it's just automatically broken, especially when only 1 of the 4 users of the 170 BP moves has actually been banned.
Again, the insane BP of V-create is balanced by substantial downsides. The recurring penalties to speed and defenses are severe. It makes it really only feasible to throw off one or maybe two before you have to switch. Fishious Rend can be spammed much easier.
Moyashi correctly pointed out that having to move first is a downside, but it is far easier to control that. And hat are we talking about here? Only going back down to the BP of liquidation? Most physical water types have that as like their normal Water STAB.
Even so, the existence of non-broken Pokemon which serve legitimate roles does serve as a counterargument to banning the move. Primeape and Arctovish are not comparable to Shadow Tag Gothita; the value of banning a move to free a single Pokemon from Ubers is extremely questionable when the amount of collateral is basically equal to the gain.
While this is true, my issue is these mons are clearly not OU level with or without the move. Primeape and Arctovish are just bad mons. So judging them by OU standards is tricky. Shadow Tag probably wouldn't be broken on, say, Sunflora. Does that mean we would have never come to the conclusion it was broken?
No it wouldn’t. Broken Pokémon have relied on far less reliable moves than Crabhammer and if Wellspring had to rely on it instead of Ivy Cudgel, it would only be marginally less consistent by virtue of slightly lower accuracy. 90% is still very accurate all things considered.
The rest is just trying to paint Cudgel as some broken move when it’s really just an exceptionally good move.
You left out the contact part as well, which further limits things like helmet chip or Flame Body. I already mentioned how this further limits counterplay options. The two things combined can make a world of difference.
As for Cudgel in general, higher BP means that the bonus multipliers also become more effective. Normally, this is balanced out by downsides. The lack of downsides makes it very consistent and hard to stop for a move of that BP.
“no drawback”
having to move first is not a small drawback when the game keeps getting faster.
While this is true, there are a two main issues. The first is we are still primarily talking about wallbreaking here. The mons using FR and BB would still be faster than most walls. However, all those mons also had the option to use their ability boost their speed tiers with weather. This means they could potentially outspeed more mons than you might expect. You don't get to use Strong Jaw or Nuzzle at the same time, but you do have control over what combination of speed and/or power you are building for.
Beyond that, the gap between 150 vs 170 looks big on paper until in practice you realize it’s overkill and it doesn’t actually make a difference in most cases. You’ll often end up OHKOing anything neutral to your 150bp move with it, while both the 170 and 150bp move are 2HKOing resists, the gap not mattering there either.
Also pointing this out. Hustle Dracozolt is only strong because it has 10 more attack, but again in most contexts won’t matter as they’re both KOing targets in the same amount of effort.
This seems overly handwavy, particularly in respects to wallbreaking. Even if it doesn't make for most frail or even average bulk mons, it would likely make a difference for bulkier mons and resists.
Higher BP means a higher bonus multiplier AND a higher starting point when adding those bonus multipliers. A 50% STAB bonus on 150 BP is only 225 compared to 255 with 170 BP. A 20 BP difference becomes a 30 BP difference, and then, the gap continues to increase with each bonus multiplier. Add an item, an ability, and maybe even a weather or terrain effect, and the differences between the two starting points will become greater and greater.
No offense but throwing “objectively” in front of your claim doesn’t make it actually objectively anything. You can’t throw out X is objectively broken without substantial study and evidence. You look at all these moves in a vacuum rather than in practice with the nuance associated. Rage Fist is designed to be used on Pokémon with good bulk/typing to build up boosts, so on frail mons it can’t work well. Fishious Rend being on slow Pokémon balances out the power it gets. Etc etc.
Is Last Respects not objectively broken? Is Shed Tail not objectively broken? Do I actually need to prove those two? I shouldn't need to. We can debate the others, I guess, but there should be an upper limit somewhere here on moves that are obviously problematic from a competitive stand point.
And the reason why I'm looking at these moves in a vacuum is because tiering policy encourages us to literally never do that. While I understand that context is important, sometimes there is a tendency to use that as an excuse to overlook the moves themselves. Personally, I think we should do both and then make an informed decision on it.
Something like Last Respects taken to an extreme would suggest that move could be balanced if it was on a slow, frail, and weak mon. If it was given to something like Tropius instead of Baculegion, would we claim Last Respects wasn't OP because it didn't "break" a ZU mon in Tropius at an OU level? To me, this is where it gets really silly.
More than anything, banning these moves fundamentally doesn’t change the outcome of the user’s fate. Ban Rage Fist and Annihilape is free in OU but it also isn’t worth using most of the time anymore. Ban Ivy Cudgel and Waterpon isn’t broken but it also isn’t usable anymore in OU. Fishies Rend, etc etc. So what do you get from banning the moves when banning the Pokémon does the same thing and with much less confusion or fuss?
Annihilape would probably still have a place as a bulky spin blocker. It would still be pretty strong, IMO. Leftovers and Phantom Force could probably be pretty good, particularly on Grassy Terrain. Waterpon would still be usable with Tera Blast, maybe, but it would become even more of a Tera hog. Sure, those mismatched fossils would all have been worthless. Not sure about the other two.
That's kinda besides the point, though. It's about balance. If moves are clearly unbalanced, we should be able to say so. I do agree that there are cases where some mons rely on a move that would be too strong for others and it winds up being ok. That's fine to a point. I just think there should be limits to that.