DKs are waaay underpowered! Check out the link below from World of Logs. Conspicuously missing from almost all of the lists are our beloved DKs, regardless of Unholy or Frost DW. I really hope Blizz makes our damage more competitive in Cata.
Switch to 25man mode (Tab at top of page) after clicking the link.
http://worldoflogs.com/rankings/play...n_Citadel/dps/