Ive never seen a warlock self res and save a raid in normal mode, but thats because usually they self res so we dont have to res them. In hard mode you cant res anyone that dies, so its a wasted super unless the ONLY person that died is the warlock themself. I wont dispute the value of self res in the nightfall because I agree that it is very useful, unless the burn is void, then i want to -blam!-ing kill any warlock that is a sunsinger.