Shame that most classes really need 80 and full exotic gear at least to reach their potential, I have 80 thief, elementalist and warrior and the warrior is almost braindead easy, at least in PvE. Thief is awesome for soloing and exploration thanks to stealth, you can open chests without having to kill mobs guarding them and they have some of the best movement skills with shadowstep and shortbow. Got 100% exploration on him. They provide some utility in groups, mostly thanks to 10s party wide stealth, you can speed up some parts of dungeons and smokescreen blocks projectiles. Blind is mostly nerfed to the ground, sadly.