If your group can't run with a warlock then ditch them they are awful. I run with 2 warlocks, 3 Titans, and 1 (sometimes 2) hunters. Let me tell you who saves the day when the taken thrall attack my DPS team on golgoroth and I kill all 15 before they can scratch my crew. Or on warpriest we have one on each side and I -blam!- up those acolytes. And when I goof on oryx I prevent wipes when I self Rez. Lol switch characters GTFO.