Classes are a little role-restrictive. Mystics and Priests can pretty much only heal, Lancers can pretty much only tank, and everything else (Archer/Sorceror/Berserker/Slayer) can only DPS, barring Warriors which can tank or DPS. From what I hear, Warrior tanking is less taking it on the chin, but more evasion tanking.
My main was a Warrior and I think I left around the time that EnMasse tried to make Warrior tanking easier. Yes, it is all about 'evasive' tanking. But, it does not mean running around everywhere with the boss in tow, cleaving the faces off of your party members as it passes em by. Your main job is to keep the boss from moving too much and positioning it, so that everyone else can hit it till it dies. While avoiding
as many attacks as possiblethe more dangerous attacks, keeping aggro and managing your energy bar.
Life as a Warrior Tank was actually satisfying, but you faced prejudice cause many more idjiots can't and actually Q up in the dungeon finder as a tank, while not expecting to tank. (Well, horror stories I heard when mention/consideration of Warrior Tank comes up in a dungeon party anyways...)
I usually didn't main tank until I ran the dungeons a few time first, so I'd at least know the fights beforehand. Though, some dungeons I considered impossible for me to tank...
Anyways, a few times the party ends up having the tank ragequit or fail hard. I end up becoming tank and we make it through. Mostly cause lancer tanks are at a premium and the other party members were game enough to try it out.
Of course, I don't know how that has changed overtime.
EDIT: Also... Warrior DPS is on the low end. Doesn't really have burst either. At least that is how I feel it was.