Sorry, I was reading this guide for my new 90 DK, but I wanted to comment on this.
As a warrior, I ran a normal raid the other night and anytime the DK taunted boss off of me, I couldn't use my dps abilities AT ALL or else I'd take the mob straight back. I cant' remember the last time I had to worry about that. I went from like 130-140k dps down to 90k dps simply because I couldn't press ANY buttons when I was off tank and just white hits kept me at 99-100% threat.
Was the DK tank just bad or is this something that DKs are facing? I've never had this problem, but I think I've always been the undergeared tank in most cases (547ilvl) so maybe him being like 545 was that big of a difference.