This is a rework that gets rid of the 'sacrifice damage for mitigation' that exists mostly (or only) for DRK. Blood becomes the defensive resource, MP is offensive.

This will require changes to abilities:

Delirium: Blood cost gone, effect stays the same (more or less the DRK IR so to speak, just a cooldown)

Bloodspiller: Now is a combo from Syphon Strike, and costs no blood. Adds 30 Blood, Potency change so it now has a damage + 30s DOT component which overall potency is greater than Souleater, but requires the DOT to run its course to do so. Dark Arts only adds 140 potency to the frontload, does nothing to the DOT.

The Blackest Night: Cost 25 Blood, shields for 20% of health, 3s cooldown. Casting it when up extends the duration and increases the shield, but only by 10% of your health. Can only cast on self.

Dark Mind: 60s cooldown, costs 25 blood. 10% magic shield for you and party members within 15y.

Sole Survivor replacement: 120s cooldown, cost 50 blood, 10s duration. Target gets 10% less INT/MND/STR/DEX. Party members that hit it during this time gain some lifesteal.

Most MP abilities stay the same.

Anything I've missed? Or does anyone have any other ways of implementing it?

This way round (MP for damage, blood for mitigation), I think is easier to do. What would you do to swap it the other way around?