K so Serebii has pictures
(which I believe are mostly from the trailer) and I guess I'll just post my thoughts on them.
If I had to guess, Hydreigon seems like the ideal Pokemon to be the game's primary antagonist. It seems like the perfect Pokemon for the job. Virizion seems like it will also play a prominent role in the game's storyline. I think Virizion could be the guild master of the game. Terrakion, Cobalion and possibly Keldeo could also possibly come into storyline, too, just as what happened with Mesprit, Azelf and Uxie.
A "magnagate" seems to a portal that appears when you use the 3DS' camera on a real life object.
This game looks amazing so far