I noticed in Greninja and Charizard's reveal trailer that the Flood Chamber and Dragonmark Chamber from the Elite Four in Pokémon X & Y appear as stages, round about the 1:45 and 2:06 marks. oddly enough they appear to be Wii U Stages. Anyway, I was surprised to see Greninja revealed to be a playable character, looks like he will be a good fighter. Can't wait for the Summer for the 3DS Version!!