Good lord almighty I want this so badly. I'm not sure what your limitations are as far as what you can actually edit in the saves, but if there's a way that you could include the capability to add spells and such to the characters, that would be awesome.
Appearance editing options perhaps? I must have restarted 20 times before I found a look that didn't look dumb in-game.
Play for a bit and you'll reach a point where you can change the appearances of your characters entirely, without having to start over. And you can do so as many times as you like, apparently.