From what we know, I'd say leave BS/Q on GCD but add Delirium's BP/BW duration extension to them. Also..
..Reduce Delirium's MP restore and remove recast, rename Blood Price to Dread Spikes and buff it so it has a built in damage reflect (30% chance to inflict 75 potency counter), add 20second +20 evasion to DA'Dark Mind, introduce the new UI gauge @ lvl45 (at least part of it) & have it provide a visual representation for stacks of Dark Arts (let DRK stack up to 3).
Buff the Dark Arts enmity effect of Power Slash, or +140 potency (seems to be the DA motto of SB), or change it to a DoT - something anything to make it viable. Change Souleater absorb so it doesn't require Grit, but in Grit the amount of health restored increases with the lower the DRK's HP (up to 2x the amount of damage dealt). Replace Blackest Night with Doom Spikes, thematically the same skill, but with guaranteed 75 potency damage counter on each hit received while barrier is still up. Trait for Salted Earth that adds a 30% chance to reset bubble's duration every time Dark Arts is used.
I'll believe Sole Survivor has TA utility when I see it. Danced to this tune before, not getting fooled again.
whew got that out of my system.