Likely new members of OU
Aegislash (solid offense and defense, good setup potential and strong movepool with good coverage)
Azumarill (Fairy typing greatly improved him, gives him a lot of good immunities and resists as well as STAB play rough)
Barbaracle (A shell smasher that actually has good stats)
Charizard (Drought will probably push him into OU territory, potential for Charizard X without being warned at team preview would make him very unpredictable but still having issues with sneaky stones)
Goodra (Solid stats, it's the pseudo, but probably the weakest pseudo ever due to an odd stat distribution, rain nerf, and lack of an ability like Dragonite's multiscale)
Greininja (Protean, a diverse movepool and solid stats including good speed make him really threatening as both a support pokemon and potentially as a sweeper)
Kefliki (prankster and decent stats with a decent support movepool)
Noivern (boomblast)
Medicham (its mega boosts its base stats and keeps pure power, his attack is so fucking ridiculous that it can make up for almost any shortcoming)
OU/RU potential (need more info on moves though IMO most megas will be banned to RU): Tyrantrum, Delphox, Vivillion, Furfrou, Dragalgae, Clawitzer, Heliolisk, Hawlucha, Gourgeist, Aggron, Banette, Mawile, Absol
Banned immediately: Gengarite