Talent suggestions:
(1) "Archmage" "Pyro/Hydro/Aero/Geo/Witch": Prerquisite 5 ranks in respective school, lowers enemy resistance to your spells of the respective school by 20%
Reason: Right now taking 5 ranks in a magic school is maybe not that great. Furthermore, specializing in a single magic school is bad because of enemy resistances and "rainbow mages" are much better. Such a fifth rank talent would make immune enemies at least slightly susceptible to the respective school. It might(?) make it worthwhile to buy five ranks.