Are Death Knights overpowered?

Taking up a subject from the open Sunday thread, and with an obvious fit to today's class balance post, I'd like to discuss whether Death Knights are overpowered. That is not an easy question. One problem is that if you only play a Death Knight to lets say level 60, you might well conclude that he is overpowered, but a good part his power at these levels comes from his starting gear. We instinctively compare the new class to something we know, how our previous classes played up to level 60. But of course *all* classes got boosted with patch 3.0.2., and when we reached level 60 back in the days before TBC, we didn't have the uber gear the Death Knight receives as part of his starting quest line.

So before we can actually make a valid comparison, we would have to play a Death Knight to level 70, and see how he fares in Northrend, in comparison to our current level 70s+. There have been reports that even there the Death Knight deals more damage than any other class, dealing more damage while tanking in a group than other classes that are pure damage dealers.

Tanking is an art that consists of two parts: Damage mitigation and holding aggro. My Priest was healer in a group with a level 75 Death Knight tank, and they are clearly inferior in damage mitigation to the other tank classes. The problem of DK tanks is that they don't have as many and as good taunting abilities as the Warrior has, they hold aggro mostly through damage dealing. But if you hold aggro by dealing damage, you need gear that gives bonuses to damage, and come up necessarily short on classic tank stats like defense. I haven't seen a frost DK in tanking action yet, everybody is unholy or blood for better damage output. I could imagine that a frost DK with 490 defense, and high values in stats like dodge, and parry, would be much better in damage mitigation, but I'm not quite sure yet how he would hold aggro when he deals less damage.

Of course when talking about "overpowered", we will have to ask "overpowered compared to what?". Up to now I don't have the impression that Death Knights are overpowered compared to Warriors, in a tanking role. In my currently still limited experience as healer of Death Knights, if I had the choice of tanks, Death Knight would rank at the bottom, below Warrior, Druid, and Paladin. But apparently the people complaining most about Death Knights are the dps classes. Undoubtedly Death Knights have far better damage mitigation, and depending on spec also self-healing capabilities than lets say a Mage. So if the Death Knight deals more damage than the mage, I can understand why the Mage would be unhappy, even if the Mage remains king in aspects like crowd control or AoE damage. Maybe the better comparison would be with a Rogue. Are Death Knights making Rogues obsolete?

And then of course there is PvP. The arena is currently in suspension, and most people are busy leveling instead of doing PvP, so there hasn't been all that much PvP involving Death Knights yet. But classes with a high damage output are potentially very powerful in PvP, especially if you add all the other goodies, like damage mitigation, self-healing, and pets to the mix.

So in summary I'd say it's still a bit early to say for me whether Death Knights are truly overpowered. Feel free to post your experiences with Death Knights here. Do you think they are overpowered?