Ok so wouldn't it be kinda fun If you could do magic rituals to accomplish more complex spells, maybe have a spell that summons a permanent creature, but it requires some items, maybe something from the creature you want to summon, some chalk, a little blood. Or you could make certain npcs sick (if they annoy you) If you wanted to really get into it you could summon a demon and make a pact that would give the user special powers. This could introduce a fun little witch/warlock/cult storyline.