Well, its kinda unfair to compare a fun class like the DRK to the currently best class in the game, warrior. Warrior is a better OT of course, since it brings debuffs (DRK doesnt as OT) and has more damage.

DRK is still in its infancy, its a fun class not able to seriously compete with the big boys. Look at Machinist, or to a lesser degree Astrologian: these classes are fun, but not in the same league as the others. But you dont have to level subclasses, you save yourselves 30 levels of exp, and they look cool.

IMO at this time, they arent serious performance classes, just toys to pass time and have some fun in roulettes.