the gambits should be letting you comp characters attack. the attack-> foe: leader's target should be first, so they will focus on attacking what you are attacking. then when you are the fighting screen, make sure the yellow G symbol is by everybody's name. if not, that means they are not using their gambits at all, regardless of weather the gambits them selves are on or not.
Even if it's not as good as I-X, I still think it's a good game. Your problem is most likely a glitch, or you've missed something about how to activate the gambits. You do know that you have to highlight them in the Gambit menu, but also turn them on somewhere else, as well? Like, through the attack menu, or something like that, I don't quite remember.