I've recently been leveling my DRK, hit 45, and have a few questions on my rotation.

Currently, I Unmend to pull, Unleash a few times to grab hate, then go with my standard enmity combo and rotate through mobs as needed. I use Blood Price to restore MP, and drop Grit to use Blood Weapon when we're down to just one monster left (If mobs are being AoEd, I just hope I don't need extra MP and try to weave in Syphon Strike here and there). On boss monsters it's much the same, except I usually do a dark arts powered heavy slash combo to start with, then drop Grit and use Blood Weapon whenever it's up.

Thing is though, I feel like I'm not living up to the potential that DRK has. Souleater is just something I fire off after Syphon Strike as a marginally better option than just swapping back to my higher damage enmity combo. Dark Arts largely goes unused due to the MP cost, as I don't need the bonus enmity once hate is established, and using it to power up Souleater, while it does seem like it might do more damage, also would take more MP than Syphon Strike restores, which is against the point of why I tend to use Syphon Strike in the first place.

Should I be risking my MP pool to swap to the Souleater combo with Dark Arts? Maintain my combo as-is? Or is there some more useful way to use these skills I've overlooked?