From the looks of it, Square Enix and their huge egos probably didn't want to allow any of their characters in the game. Maybe because they already have Dissidia, or maybe because it's their "baby" and they don't want to let anyone touch their characters. Jeez have you guys seen their conference about Lightning? They're ****ing obsessed with her.
Square Enix just ****ing annoys the **** out of me throughout this whole generation.