I'm surprised no one is talking about Mega Kangaskhan, or Mega Lucario yet, I don't think Mega Gengar was mentioned yet either. But I may have just missed something someone said. As far as Mega Lucario is concerned, I'm perfectly fine with it staying OU, however, I can see it being Ubers because of how well it runs both Physical and Special sets. You won't know what set it's running until you see it set up, and often it might be too late to react. If you see one and think "Oh, it's gonna be physical, so I'll just switch to my physical wall and cripple it." Boom, Nasty Plot, and vice versa. I can't even think of much that even walls Mega Lucario either, besides Jellicent walling the Physical variant.(Unless it carries Crunch). The same argument has probably been made elsewhere, so I won't really elaborate any further.
On to Mega Kangaskhan. I'll be honest, I don't have much experience with 6gen battling, but from what I have experienced, combined with what I've seen from popular wifi battlers(examples being shofu, pokeaimMD, etc) this thing is extremely powerful. Every battle I've seen with it before its ban, it almost always stomped through the opponents team. Granted there were a few times where it failed to do so. Obviously, my word isn't to be trusted as much as someone who has battled a lot. I'm basically just typing from what I remember. I'm sure someone will address these Pokemon better than I can.
That being said, the other Pokemon should be addressed as well. That's why they're suspect to begin with.