That is an interesting idea. However, to be honest, if I were to put in more work into Oubliette (aside from maintenance changes), I would much rather put effort into making a multi-player version like the original. Although this single player game can be fun, it is but a shadow of the original. Imagine playing where the party you are in consisted of 5 or 6 other REAL people, each controlling one character. The original Oubliette was a much more social game, much like the 'paper dnd' which inspired it.
That being said, your enhancement might be useful for such a future version. I need to be careful about the concept of 'balanced' classes, however. If you try and do that, you usually end up with all the classes pretty much being the same. I think that a better approach (which I try somewhat in this version) is to tie a class's relative power to the rate at which they can advance. Hence the lesser classes can advance much faster than the better ones. Still, I would like for each class in the game to have SOME use.