Voidwalker does not have the best grenade for any situation -- they actually have some of the worst. Their super is easy to miss as opposed to Titan. They are good for zone control and AoE. Sunsinger is super weak in PvP -- probably the weakest PvP class. Not everyone has Heart, and even then it's the difference between a kill and overkill -- doesn't overly matter. Scorch is good when radianced but happens once per radiance. Warlocks are great in PvE but you're foolish to think they're op in PvP.