if you stand before a boss who hits 6mio+ per hit you wanna be a pally
Or scout
i would say pally cuz you can tank without healer also you can support your party with perma off/def buffs
Scout can also tank bosses without a healer (and for packs I don't think pally doesn't need healer), support his group with perma deff buff, give group shields, offheal his group, deal decent damage and self-puri.
And there are lots of warriors tanking top PvE content without problems, being probably hardest tank to kill on BG.
So it's all a matter of taste eventually.