As someone who has quit destiny but still lurks here, (i have no reason to be biased) it's because Warlocks are more annoying. Hunters are probably the most OP class, but such a large majority of people main Hunter that ya'll are immune to it. Warlock self res, nova bomb, and grenades are deadly, and people aren't as used to it. I was pissed when a warlock killed me, but hunters and titans are whatever.