Màximus I play priest rogue (at 1800 -.-) our tact vs DK setups is that , me and the priest stays close to their healer all the time so the DK cant be at the other side of the arena and grip u.
so just stick togeather with ur teammate and stick close to their healer.
i have not played wow since BC but i would assume that he runs wound/deadly, otherwise those 3 extra pts in assass would be pointless...and he wouldnt be able to envenom