Looking over the psionics, it looks like they don't really gain any over the noble...a few just move to "at will". Do we want to raise the caster level higher than 20th, or maybe add a few more abilities?
Let's think about adding a few more abilities. CL/ML higher than 20 is pretty unusual for non-uniques, right? Not that I'm absolutely opposed, but we should think carefully before going higher.
Looking over the psionics, it looks like they don't really gain any over the noble...a few just move to "at will". Do we want to raise the caster level higher than 20th, or maybe add a few more abilities?
It would depend on our desired CR. If we give 'em 20 levels, this thing is going to be around solar in power (CR 22). If we'd prefer more in the CR 16 ballpark, like a planetar, then 17 levels is about right.