The OP's idea is very similar to what 3.0e psionics did. Everyone said 3.0e psionics sucked because it forced them to be MAD. Personally, I liked the fact that it forced psionics to be MAD. As primary "casters", they need something to take them down a notch.

As such, this seems like a good idea.

My only real concern is that it messes up the house rules I have which divides up the schools of magic in a completely different manner (I use 16 colleges which do things very differently, rather than the 8 schools).