I have 3 warlocks and i still havent gotten the raid helm. But if you have all 3 other raid pieces then i recommend you hope for the Light Beyond Nemesis exotic helm. That way you can hit 30. Plus, being a lvl 30 sunsinger who can not only self revive, but also revive others faster and they revive you faster is a highly useful character and people will always want you in their teams for nightfall or normal raid. In hard raid though the helmet is kinda useless since you can't revive anyone. But basically i say make a 3rd warlock. The less gear you need to track down the better and easier it is to keep yourself maxed out and full on materials.