I don't think that the Drive System will be back in the next Kingdom Hearts series. The reason why I think so is because Sora would of grown out of his Kingdom Hearts 2 clothing. But I think that Sqaure Enix will get rid of the drive system anyway because they are likely to start off fresh meaning new abilities and a better combat system. If Sora somehow gets the ability to duel wield Keyblades, I hope that the enemies are much harder because fighting will two Keyblades all the time would make the game really easy. Duel wielding Sora would not be to much of a bad idea though.