DK desperatelly need healing, awa DK have 1 semi useable skills that heal for ~320HP per target and have 6s CD (require to attack target, very long&slow skill cannot be used in PVP).
Class basically have no healing at all, both PVP and PVE suffer alot if you drop low, you have to run away and potion up for like 40 seconds.
Goodluck~