I loved Druid tanks in World of Wacraft and also Death Knights which chose to stack heavy mitigation stats over just "HP" because they didn't have the defensive stats of the paladin and warriors which had shields. There-fore it was fun going several attacks in a row never taking a true hit of damage because it was dodged or parried or even blocked. I found that fun and disliked when they, and consequently this game, has gone to homogenized "active" mitigation. Everyone has their -20% incoming damage for x duration, -30% incoming damage for x duration, +to Healing Received...+% Increase to Block damage...yawn. They all play roughly the same.

I think a tank that focuses on taking as few hits as possible rather than just reducing the damage but still taking every hit is way more interesting and fun. Fancy foot-work, dodging, countering and parrying are all more fun to me than pressing whatever -20% incoming damage ability. In this way Samurai would actually make sense as a tank to me. I just don't see them as takers of massive, heavy punishment. So either an evasion tank or a DPS.