>>20045696ADV and DPPt were not centralized at all. There were top threats, and they were common, but they really weren't centralizing.
Gamefreak went crazy with with the power creep in Gen 5, with the hidden abilities, Drizzle/Drought on non-ubers, Shell Smash, Genies, Muskateers, Gems, etc. XY pushed it up another level with megas, Steel nerf and Knock Off buff, Fairy typed Azumarill, and other things.
Mega Kangaskhan was bulkier than Mew and has 213 effective base attack, as well as an expansive movepool. Mega Luke was a CB Terrakion with Keldeo blah blah blah. Mega Gengar had uber-level Spe and SpA with Shadow Tag. Mega Maw has 260 effective base attack, X-zard is a ridiculously scary Dragon Dancer with high-powered STABs with great coverage, Mega T-Tar and Gyarados are bulky as fuck and are also good Dragon Dancers. And then there's stuff like Mega Gardevoir (tears stall apart,) Mega Medicham (strongest attack in the game, discounted certain choice/weather boosted moves,) and Mega Heracross (bulkier than the other two and still hits really hard.)
Not being "ban happy" and just letting the meta "adapt" isn't an option anymore. There's just way too much power creep.