There isn't a need for another tank class. There's a need for less DPS classes.

I don't usually play a tank. My forte is playing the role of melee DPS. But I always play an unstoppable heavily armored unit in every game I play, because that's the kind of class that I like the most.

Like me, I believe people choose to play the class that they do because there is something that they like about it that is not relevant to the role that it serves in a group environment.

Melee DPS are pretty popular in games like these, yet the incentive to not stack them is generally to just have them die instantly when they mess up or make an encounter more difficult if you have too many of them. Sometimes I just wonder why all melee DPS aren't just tanks.