The way I see it, at this point the meta is dominated by 2 overpowered circles:
the mega wall fuckers: mawile, char x, char y, cross, cham, gard, pinsir. If I don't get at least 2 kills a game using one of these, I'll be pissed.
^seriously these things are all obscenely "broken" under gen4-5 pretense, without exception
the non-mega assholes of the tier: thundurus, landorus, keldeo, terrakion, azumarill, latios, (maybe gengar). Fast, powerful, and overly fast and powerful
^spammed on nearly every team, and are on their own tier of powerful. maybe not broken, but overpowered yes.
the entire meta can be defined by the struggle to live by these 2 circles of pokemon. You have the over-reliance on speedy pokemon to check these, including a super anti-meta use of mega dactyl, zam, and manectric (I've seen all of these used to good effect at 1800+), and the over-usage of choice scarf revengers in the tier (tyranitar, mamoswine, diggersby, heatran, magnezone) as well as greninja + talonflame. You have stall that beats teams that beat wall breaker teams, which beat stall teams. Diversity is increasing after post-aegi, but decreasing as well. Pokemon such as manaphy, hippowdon, chansey, etc are phasing into irrelevancy, as we reach a "super A/A+/S" tier that will represent 90% of OU.
Staying on topic... I think mawile is much less broken than other likes (Charizard, I'm looking at you), but still broken to the point of deserving a ban, much like staraptor of gen5 UU which was simply too strong. But then I wonder, in a post-aegi meta that is offense oriented, I don't think it's broken. We could, in theory, get used to a new offensive type meta that revolves around momentum, and sweeps. After all, stuff like gen4 stall was stupid as hell, and hazard wars were also stale. I'm a believer of pokemon to be a naturally offensive game, with stall being only a niche strategy.
Like basketball, it's about who scores faster. Not like soccer per se, which can be about keeping it 0-0 till one person breaks through at the end to make it 1-0 (Cringe analogy, but I hope you get the point). In a meta all about attacking and killing at the most efficient and strategic way (yes, there is strategy in this. HO vs HO is one of the toughest-on-the-brain match ups), I don't see mawile broken at all.
But if we want to go back to a meta like gen4/5, with reasonably balanced offense and defense, then you're being slow. You're going to have to ban like 5-8 pokemon (see above), which at this rate, will take 2-3 years. GL with that, especially with like 10 more new megas coming.