Confused about DRK complaints

[Zolentus]

Dark Arts with Dark Dance - adds 20% evasion to the 30% extra parry - great mitigation in big packs
Dark Arts with Souleater - 400 potency instead of 260, bigger self heal, more damage
Dark Arts with Dark Passenger - adds blind effect - enemies more likely to miss - more mitigation
Dark Arts with Abyssal Drain - absorbs AOE damage as HP

Don't forget:

Dark Arts with Dark Mind = Increase from 15% to 30% damage reduction against magical attacks.

This particular combination turns the Tankbuster (a series of rays following the move Discord) in the final phase of Alexander - Burden of the Father from a horrific juggling match for healers into a manageable speed bump. And its 60 second cooldown fits in perfectly with the rotation for this move, so it's up every time. There's a few other fights where it finds use, but here's where it presently shines. It also emphasizes the importance of MP management and combat awareness for Dark Knights.