If you look at the historical technique on how greatswords and claymores were actually used in combat you would understand that the animations for Dark Knight are pretty accurate. Even if this is a fantasy game, using semi-realistic sprites in a MMO setting can only go so far in regards to combat style and effect animations for such weapon. Most of the people I hear having a issue with Dark Knight is the same people who mained a melee or dps class other than a tank and them coming into Dark Knight with the mentality and technique of such dps class focusing always on single targets with large pulls. Being a Ilvl 177 Dark Knight, I find the job amazing being able to manually apply my dots on all targets, laying down a great aoe and also blasting all enemies with Abyssal Drain so when the dps go to that mob they are 3/4 or even half of their life left making pulls and dungeons so much better and quicker. Whichever tanks class you chose to play....make a choice on what you enjoy about tanking, being as you said a living holy wall, a tank with amazing single target potential of a warrior as a off tank, or as a tank spec that has one of the most potent AOE potentials for a melee in game with great abilities that can be used under certain circumstances.