I am so happy they didn't just gloss up the Stadium/Colosseum battle mechanic. This one looks much better.
As for the starters, the Chespin ooks very strange, but I predict the Froakie will be the ensemble darkhorse. And have a million "Kermit" nicknames.
As for the legendaries, the bird one looked initially like the Thundurus bird form, while the deer Legendary reminds me way too much of the deer from Princess Mononoke.
Also awesome that we'll be getting the game at the same time as Japan.