The tank was another DK, frost spec. He was defense capped, but he was duel wielding. I know DK.info has an official thread regarding duel wielding and so far the gist is, with enough hit and expertise it might be viable.
I was worried about Parry-Haste but that doesn't seem to have been an issue with only 22 parries he caused. He did go down faster than Brittany's Spears' career and I don't know why. He has the big three early mitigation talents. Maybe we had bad healers, since we had two of them. Not sure.
What really amazed me was the threat problems. On AOE pulls, just pestilence and unholy blight were grabbing aggro from him in a big way. I didn't even think about using DnD. I'm sure his lack of threat is due to low hit and expertise, especially for a duel wielder.
Holy Crap!!! 17% Miss, 10% Glance, add in another 5% between Parry and Dodge, he only landed 67% of his attacks cleanly. Here I was bitching that my glance and miss were 15% combined and was not pleased with the impact it had on my output.
There is something to be said for BC's heroic requirements as well. We had a rogue in the group that was sporting 807 dps. That's acceptable, if you're T4 and level 70. Quite honestly, I don't think the big boy guilds would take me for dps with my 1500 in their heroics, and I'm OK with that.