As you can see from Rhidian's work, the only way to really modify talents is to script effects that are applied if a player has a certain talent. You can't rename talents to traits or rename the talents, but you can do certain changes by scripting a permanent effect on your character if you take a talent. Your particular ideas might be somewhat hard to implement. I'm not sure if you can augment the damage or effectiveness for skills from one particular school.
One thing that might be fairly easy is making talents mutually exclusive. The "Requirements" stats file appears to do that. I haven't tried messing around with it, but I imagine that would work.
