I would rather have different mechanics then the ones given altogether and change the flavor of the class to be less like Samurai and Paladin, Warrior altogether.
Like, really though. Magic Defense Tank? Parry? Really?
Warrior Stance dancing is so much funner of a mechanic, also very rewarding. Dark Knight feels more like a chore to play then fun, you don't really get a rewarding feeling for playing the class.
Dark Knight would be a heck of a lot more interesting if it was based off sacrifice, lifetaps and sustain through magic and had its own flavor and well; just not be a copy of the other two classes with Samurai skills thrown in. Look at the Dark Knight abilities in FFXI:
http://ffxiclopedia.wikia.com/wiki/Dark_Knight
Look how interesting those abilities are. It can work if you PUT effort into making it work.
What I suggest, is merely making the Tank more like Dark Knight should be.
Flavor and Lore should be the biggest part of any class. When you don't have either you have something broken.
No, I don't use a Parser. I look at abilities and see a higher potential of damage. However, admitting to using a parser is a bannable offense, do you use one? If so tell me so I can report you. :P