Honestly, the only thing you'd have to do to keep this version of Sole Survivor from getting out of hand is to make the Vulnerability Up debuff the same as Trick Attack, so that they overwrite one another instead of stacking. (which I believe is/was already the case in PvP).

10 seconds of 10% damage up is problematic from a balance perspective if you can use it on top of all the current raid buffs, because then (using current gear/damage as a reference) you're adding 10% of 50-70k damage every 120s, which works out to an increase of 416~583 average DPS.

If you can only use it outside of the rest of your party's raid buffs, then you're only adding 10% of 29-33k damage every 120s, which is only 241-275 DPS. That's basically how far behind in damage DRK is, so there's really no balance issue with that - especially considering that DRK should be dealing the highest tank DPS given the numerous disadvantages they have in terms of personal mitigation, party mitigation, utility/self-sufficiency, and burst damage compared to WAR.


Re: The changes to Bloodspiller and Dark Mind:

Bloodspiller is kind of a tricky one, in the sense that TBN sort of ties Bloodspiller's potency to the potency of Dark Arts and your basic Souleater combo. However, honestly, Bloodspiller should be stronger than it is - a skill you get at level 68 should feel more rewarding and powerful than a skill you get at level 54 (Fell Cleave). I think that this change would be good, but requires an associated change to The Blackest Night, to reward only 30 Blood on a shield break instead of 50 (with 500 potency on Bloodspiller, that 30 Blood would be worth ~137 potency, whereas 50 Blood with the current version of Bloodspiller is worth ~134 potency).
I would also go ahead and just fix the Grit potency values so that the damage penalty is nullified, as the skill was intended to be used. With 500/640 outside of Grit, that would mean 625 base potency in Grit, and 800 with Dark Arts.


I don't really agree with this change to Dark Mind, though. The problem with Dark Mind isn't really that it isn't strong enough as a cooldown versus magic damage - it's that it's worthless against physical damage. I would either just change it to universal mitigation, or (if you really want to maintain the flavour of being a magic-specialized cooldown) give it a souped-up version of Dark Dance, with a 50% chance to Parry on a non-DA DM, and 100% chance to parry when used with DA.