Majority of players play pve? Source?

Well, every subclass is kind of subjective to their uses, but I see what you mean. The warlock's Lightbearer was specifically meant to be pvp based, but it also fills the same niche as the hunter's Bladedancer, mainly in the ability to literally rush across wide distances or revive teammates quickly in pve. The titan's Spartan shows use in pvp as well as pve with it's devastating Gjallarhorn-like super, regular heavy ammo regeneration from melee and grenades are also a plus in pve. The hunter's Voidreaver may show the least use in pve, but it's main use is for crowd control, being able to disorient groups of enemies and rapidly dispatch them with the dragon transformation. The additional super energy gain to your teammates and the buffs you (can) give to them can make your entire fireteam unstoppable in most situations.