-Auto-Refresh, or an MP-gain ability, along the lines of "Your next hit will convert x% of damage dealt into MP gained."
-Adjust Souleater to deal 10% of HP as additional damage, while subtracting 10% of *MP* from the DRK using it.
-Increased Parry skill rating to give Tactical Parry some reason to exist.
I'm sure I can think of a few others, given time.
