NO. No, no, no. Again, no.
Magic schools are single most unique aspect of ToME, and also, IMHO, the coolest. Thanks to them, you can have a mage who specializes in fire magic at the cost of not having good healing spells, or a priest who dabbles in earth or water magic. You can customize characters far more than in other variants.
The magic schools system is good as it is. Add more shools, and you not only run the risk of turning the magic system into something big and clunky, but make the game much harder (since you have to spread out skill points even more); reduce the number, and, as well as possibly making the game annoyingly easy, you make it harder to customize magic-using characters. Suppose that Temporal and Conveyance got lumped together? Then any high-level char with Essence of Speed could also be able to teleport. Earth and Nature? Anyone who could cause an earthquake would also be able to heal themselves whenever they wanted.
What about splitting schools? Suppose that Divination were split into Identification and Detection schools: to be able to both identify items and detect traps and monsters, you'd have to invest in two
schools, wasting precious skill points!
Adding new schools? That could
work, but it would depend on what was in the new school, and adjustments to skill-learning efficiency might have to be made. Take, for example, and "item branding" school. Should it be lumped under Meta? Should skills in other schools be required for certain brands? Should item branding be an ability? (That is, do we need multiple spells for something that could use a single spell?) Or should the school not be added, its function left to Alchemy? (Remember, there will
be a new alchemy system at some point.)
Basically, what I'm saying is that the school system not only works "well enough", it works exceptionally well. Messing around with it could prove not only useless, but problematic. It works; unless you know damn well what you're doing, leave it alone.
Edit: Whoops. Less than a minute after posting this, i realized I was too late. D'oh!