I'm was already quite a fan of Pancham and now also of Gorondo. I hope we can catch him early in-game, so I can play through the story with him. I like that there is finally a Dark/Psychic-type Pokémon, and I will definitely add it to my rotation team. I'm disappointed Clauncher won't be in Y, so I'll have to trade it. I think there are quite a lot pure Fairy-type Pokémon now, and hope some of them gain types upon evolution. I like the design of the new Fairy-types, though.
I'm happy with the types of the Legendary Pokémon. I understand that they didn't make Xerneas a Grass-type, since it is not based on a plant. It is the Pokémon of Life, so it makes sense to have plants surrounding it. I still think a second type (I thought it had some Steel-type characteristics) would have been nice, though.