Twave on natu has pretty significant issues, mainly losing every natu duel and not being to safely attack in teams with like frill/ trace pory without losing a lot of momentum, again, making ur team wayyy worst jsut so u dont isnta lose to magby. Magby can also run sub if it wants to scout anyways, and if u twave the sub ur basically completly fucked." Magby can setup on 3 of the most common pokemon in the tier; Natu, Koffing, and Pawniard. "
1- Natu
* Natu can run twave so it'd be stupid to setup Magby without scouting Natu's set.
* 36 SpA Natu Psychic vs. 0 HP / 0 SpD Magby: 12-15 (60 - 75%) -- 6.3% chance to OHKO after Stealth Rock
Possible damage amounts: (12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 15).
Ok you need rock but with rock you can kill Magby with Psychic + Fake Out or Grassy Glide.
u cannot run twave unless u have another pokemon with rocks, which is pretty easy to see from preview, this isnt fool proof at all. Also this is the best case scenario, where u dont have screens up, and ur mienfoo is still alive to revenge ko, and it isnt burned, and the magby isnt protect, and theres no terrain (the healing puts u out of fake out range).3- Pawniard
* Like Natu, Pawn can run twave.
* 156 Atk Pawniard Knock Off vs. 0 HP / 0 Def Magby: 12-15 (60 - 75%) -- 6.3% chance to OHKO after Stealth Rock
Possible damage amounts: (12, 12, 12, 12, 12, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 15)
With rock again but it's the same as Natu.
Priority: If ur grookey is lo it just dies to mach, evio doesnt do that much anyways, pawn dies to mach, foo has issues of needing sac half ur team most of the time, timburr exists ig but if ur not in mach range (not too hard with screens), u die.In conclusion, ok try to setup Magby on Koffing, Natu or Pawn but do it without rocks and without a prio user able to revenge kill, or a scarf user, or a bulky mon who can take 1 hit from +6 Magby...
Once again, if we ban Magby only to nerf HO then it's a bad idea imo. If Tyrunt was suspect, should we ban it in order to nerf HO? I think this is a flawed logic.
Scarfers: Mudbray, frillish, golett, thats ur options, they arent splashable at all+ they kinda suck lol.
"a bulky mon who can take 1 hit from +6 Magby...": Onix has the issue of usually the tyrunt check, so its not at full, runt is iffy ig? Both of these generally arent amazing anyways since its hard to setup vs cheese and u can get trapped. Tho ig they are better than nothing and dont suck. Tho mandating one of these on every team is unreasonable.
Finally, tyrunt has wayyyy more offensive and defensive checks, didnt bother counting exactly but imo its a pretty reasonable amount for a mon that isnt as all or nothing as magby and its a lot easier to soft check with simple move slot edits. I know you said this as a hypothetical and not an actual thing but magby is wayyyyyyyy more limiting in therms of building and way more Degenerate in therms of in game than any other single pokemon that is currently legal.
Tyrunt is also used as a wincon on balance since it doesnt require as much assistance as magby, theirfore it would cause much more collateral on the meta as whole, vs the only collateral of magby being the end of that one guy on ladder who uses toxic magby.