Kefka as a playable character?

Ah I don't know about that one, a good Kefka hack for me would be to be able to control him as a sick evil villain still, as his normal self in other words. Filling in the gaps in between the normal FFVI events. Or a prequel of him growing up that leads up to his current state, or a combo of both. I doubt the TC was wanting to play him as a hero doing what the FF6 good guys were trying to do (save the world)...But to each is own!

A hero/villain swap hack for him just seems kinda lame imo compared to what can be done, and I doubt anyone would like Kefka because he is trying to save the world. Your idea would be much easier for a beginner to complete though and probably could come out decent if enough was done with it. Maybe he could keep his crazy evil attitude and still have some reason to save the world, if that's what you mean. Although I can't imagine what it'd be.