While i would understand why Warlocks would have invisibility over hunters, getting rid of it on hunters to give to warlocks would be retarded. The Hunter is the stealth class of the game, therefore going invisible is the best choice for it, the Warlock is the all around class. Can do insane amounts of damage or can be the anchor to help complete a strike. The titan is the tank obviously, deal and take tons of damage without dying. It just wouldn't make sense