OK well I have some overkill answers. I guess I've been waiting for years to complain. A long time ago there was a game called PsiOps - The Mindgate Conspiracy. There were powers in that game I have never seen since = {Telekinesis, Remote Viewing, Pyrokinesis, Mind Control, Aura View, and Mind Drain}. Obviously Bungie would have to rename them, but Telekinesis has got to be an obvious one. When I think about elemental powers (and I always play a Battlemage) it's really all about picking one and amping it to the max. So if the Warlocks only had Fire, that would be fine, so long as it's a huge raging burst of hotness. The ability to walk or see through walls is always cool, and probly not hard to program. I'm really kind of obsessed with area denial abilities. So my favorite skill would be for a Warlock to make a mind control spell - something that effectively works like a flashbang grenade but makes you stupid, or drop your weapons or money or something. Some force impervious to armor.