Nope. Nope. Nope.
Folks, what makes psionics "different" than magic? If it's just flavor, then reskin. What made psionics unique in the first few editions? It was a facet of your character, not the whole definition. It was a part of the whole, something that didn't come up all of the time, but was cool when it did. Then 3e+ (actually the 2e sourcebooks, but that was just the zygote of 3e's philosophy) came along with the idea that "Hey, if it was cool as a part, why not make it the whole focus of the character?" Which ruined the whole thing. That way lies bloat and madness...
If you want a class that can spontaneously do amazing things that normal people can't, I've got a revolutionary concept for it. Call it a "wizard"... No? How 'bout a "sorceror"? Still not good enough? A "warlock", perhaps? What makes you think that a psionic class will ever be anything other than the previous three reskinned? It won't, so long as you dedicate the character to the concept. Psionics were new, unique, fun, because they were a special nugget, not the whole dinner.
The feat idea someone mentioned above is pretty good. Maybe make mental combat only effective against other psionics, so that you don't get balance issues. Maybe each feat gives you a choice of 1 attack, 1 defense, and 1 utility power from a list. Later feats can give more choices or increase the power of the original choices. Anything beyond this is doomed to just create another wizard or warlock class reflavored.