I know there was a discussion about what classes/kits should be added next, but anyway.
What about a psionic class?
There were psi characters in Dark Sun and I there are also some (or a lot) in the Forgotten Realms
and Planescape. The class that I have seen (in the Psionic's Handbook?) was a bit suicidal, If I Recall Correctly,
having a 10% chance to die when using the Desintegrate Power, but at least it was another way to have
non-divine healing. And it's always nice to have that in D&D.
The psionic classes in 3E also weren't that bad and there also was some psi in 1E AD&D, I think.