To be honest I used to think the same thing and now I run my hunter all the time. Pvp they are wrecking machines with arc blade and golden gun and although they are quite squishy in pve they still have their benefits. Invisibility and agility in pve is awesome for res and escape, but their supers do eat balls when it comes to any major. In pvp invisibility keeps you off the radar long enough to get within striking distance and get the first shot / grenade out, also I think everyone who has played crucible has seen their entire team be murdered by a rampaging holden gun or arc blade. I suppose it's all just personal preference though, I enjoy each class, but I tend to favor warlock and hunter.