How about an edge for conjurers similar to what invokers have? Or, just make the "elementalist of the golden grimoire" edge available to conjurers as well, but applicable to their servitors. This is not just for elementals. Angels use area spells as well, and end up blasting goodie NPCs to pieces with their pillars of lightning. A common place to see this is in the frozen wastelands where trail rangers camo, and you have no idea they're in the room until a pillar comes down and roasts them for an UNSPEAK and -30 xp for you