a unique style for every character, so when they're fighting togethor it'll be even more amazing than the game footage in the trailer. Team combination moves, and none of the becoming other characters like in FFX with sphere grids, or materia in FF7 you know? So the characters are more unique if you get what I mean.
And of course, lots and lots of summons. Not just about ten, like as many as there were in 6, that'd be AMAZING... Although I highly doubt that would happen but still!