Playstyle of 1v1 is something that we cannot really touch. It just changes based on metagame brands, how would you even fix bulky offense? Do you want to ban Crustle, Donphan, Mega Metagross and Sawk? That's seriously impossible and out of hands. Running bulky offense in 1v1 is like THE playstyle to go as you want to tank hits as much as you want to retaliate even harder. And I wonder how you think Bulky offense is something bad in the metagame yet you are anti-ban for Mega Gyarados? That Pokemon is one of the faces of Bulky Offense in 1v1. Also your "statement" seems probably not a hundred percent true, there's lot of offensive Pokemon still running around which even the best defensive spreads cannot touch such as Greninja, Porygon-Z, Tapu Koko, some Zard X and Kyub and more... While Stall can still be present but not many people like using such tactics, but we still see the Deoxys-D, Chansey, Whimsicott, Mega Slowbro... Also we shouldn't categorize teams as playstyle, it's the Pokemon itself that is the playstyle.The State of the Meta: It's not in a good state. Bulky Offense has dominated the metagame, likely since gen 6. It makes sense, being able to sponge attacks and retaliate strongly works very well in a 1v1 situation. However, it's never been this polarizing. Gyarados-Mega isn't the only offender. Crustle, Donphan, Mega Metagross, and Sawk can easily be considered Bulky Offense threats. Even typically Offensive threats are sacrificing Speed and Power for bulk, beyond Charizard-Mega-X, and Kyurem-B. Standard Offense and Stall don't have a chance against these threats. Thanks to Z-Moves this playstyle is incredibly popular and effective. If you don't believe me ask Porygon-Z and Greninja.
Your first statement about it having the highest attack in the game with the best defensive typing is true but it isn't necessarily broken. We cannot compare last generation to this generation. Last gen prominent threats were infact weak to Mega Mawile but this gen a lot of things have changed. Donphan, Tapu Koko, Crustle, Charizard X have a chance against Mega Mawile. No I'm not saying it's not broken right now, I'm saying that we cannot judge for the time being without having it back in 1v1 firstly.Mega Mawile: Please, please, please, please, no. This monster is insane. It already has the highest attack stat in the game, combined with the best defensive typing, intimidate, and good physical and special bulk, priority, set-up moves, taunt, metal burst, and great Dual STAB, why would this thing ever be allowed in 1v1 in the first place. And no, the sucker punch nerf is not enough to keep this thing from being absolutely broken. The meta doesn't need this monster. PLEASE.
That's a topic I can seriously get behind after we take out more problematic stuff before and I really want to go more deep into it so I'm leaving it for the end. At this moment the procedure that we will take in discussion is:Z Moves: I know most people in the community agree that there has been a consensus about Z moves the last time we talked about them, but we talked about them in a much more nascent meta. Z-status moves had just started being discovered. Hell KyuB wasn't even considering running Icium Z. The discussion was centered around Tapu Koko mostly, which I doubt many people would consider the best Z-user nowadays and IF Mega Gyarados gets banned our BEST answer to Z-users will be gone and they'll be excessively splashed on to most pokemon.
-Mega Gyarados post Mega Mawile
-Mega Mawile
-Z-moves.