DKs are ridiculous.
The other day I was riding around in Grizzly Hills or whatever, and I pass this DK. World PVP is pretty dead when an Xpac is new, so I don't pay him half a mind. He BLASTS me with something, and my first instinct is keep riding. Hard to win a fight when someone gets the first hit in.
But before I even make it a few feet, I noticed that like half my life is gone, maybe a little more. This Goddamn dude nuked me for about 5000 in 5 seconds. I'm slowed and halfway dead, so I dismount to fight him. Before I'm even fully dismounted, I'm down to about 20% health. Popped a NS healing wave and got back up to around 50%, and then was dead 5 seconds later. Don't think I ever so much as laid a finger on him.
I assumed I'd been ganked by some level 80 (currently 75), but nope, this dude was 75 as well. He simply obliterated me, man handled me as a parent would discipline an unruly child.