using the Core is another bad example. mainly because whos the problem there, Deo-S or Bisharp? its Bisharp, he's the one sweeping teams with the boost, not Deoxys, Deo-D and Garchomp (To a lesser extent) would take its place. and although the core is good i also feel its not broken, Its still quad weak to fighting and Conkeldurr is a thing and he takes Sharp to town on the revenge, along with anything that can live a +2 sucker punch and retaliate with a fighting move, which is a bit. the core is not busted and if thats the best argument for Deo-s than its not busted either.
Red is where i should have stopped reading. BellyJet Azu is mediocre at best, its best set is still band, it just has that beautiful typing now. Also your dismissal of Slowbro and Tangrowth because of Assault Vest is appalling. its the same concept as Conk, they still heal off with the Vest Equipped and patch up their weaker defence. Slowbro especially makes good use of it. Celebi is also surprisingly good in a meta ran by flying and ghost. its not as good but its still OU viable. Jirachi makes for an excellent scarfer, its still has 100 stats all around, although it is worse now. These pokemon have valuable niches in OU right now (Ironically the ones you bashed most are most viable)
you also seem to assume Deo-S will guess right on the switch, although it can deal with everything in the meta, most well built teams have 3-4 checks and a bunch of priority its pathetic Espeed can't kill. i compare it to Hydreigon last gen. its got something for everything but its more than manageable.