i have succesefuly edited string file and changed Necromancers into Warlocks
you can as well change such things as gods and races names - its all pure text (it may still appear as necro on things like AA tabs i think)
btw I have tried altering at what level a class can get a skill - and NPC GM would stil not train me (to be specific I tried giving bard dual wield at lev 5) - have anyone has been able to change this with success?