I have been having little to no issues with DRK. Aggro is never an issue, and MP is rarely a problem. I just don't think many people have figured out how to optimize damage while not blowing all your MP. Also Carve and Spit is really misunderstood imo, it's a free 884 MP that's off the GCD and honestly functions better in that aspect than just a DPS gain.

DRK is about riding that fine line between damage and aggro. A lot of tanks are always trying to push bigger numbers, and I'm cool with that, that's just not me. I like seeing the big numbers like everyone else, but not if it means sacrificing more MP than I need to just for a better parse. Focusing on when to use your cooldowns and using them correctly makes DRK pretty sturdy. After running PLD throughout 2.0 DRK is a nice change of pace with a bit more attention needed. I play a tank job to tank, my DPS is good because I have a good rotation but my main goal is aggro.

DRK will never do as much damage as WAR, or be a turtle like PLD, but then again you're not a PLD/WAR so play like a DRK.