A lot of them )
1) You can do as I did in Phoenix-Mod: custom skill system. It means that default hero leveling dialog becomes useless.
Quote:2) S$1/$2/$3; Set primary and secondary skills that a hero can take. $1 = Set/check/get a +1 primary skill (0...3) Format PK. $2 = Set a next level of left second skill (-2,-1.0..27) Format SS -2 = do not change -1 = not allowed to choose (no skill) 0... = number of secondary skill $3 = Set a next level of right second skill (-2,-1.0..27) Format SS
You can use HL trigger and replace expert schools with another skill or (if no more slots)
Code:
-1 = not allowed to choose (no skill)
3) Before battle save states of for magic skills of both heroes and set to advanced magic if expert magic is detected. After battle restore previous values.