If they keep the drive system, make wisdom less useless since master and final have better magic and can attack. Wisdom form should make the keyblade grow longer into a staff that can be swung around you all cool-like instead of that stupid shot attack. If they have to keep wisdom the way it is, atleast make it's magic better than master/final to make up it's suckage.
Make the enemies much harder, and to make up for it, allow the guard ability to be held continuously rather than a second, and throw in some cool blocking animations with that. Another way to enhance it's looks would be that Sora and the enemies don't land on their feet after taking a heavy hit, rather, it would look cool if they slammed on the ground and slid a good ten feet across the pavement, kicking up dust. (which gives me the idea to include an optional ability for Sora to kick back up and hit an enemy, like the way Riku could kick you when he fell in KH1, destiny island fight)
Heck, why not even give Sora the ability the grab an enemy and throw it? (Tombstone piledriver, lol, ok maybe just toss it across the room into a wall.)