Death rune mastery is important, -- you can pestilence anywhere in the cycle and and that pestilence will turn a blood rune on CD into a death rune when it comes up so the obliterates actually come really quick.
A lot of the theory craft i read seems to comparing 1 obliterate to a it/ps disease refresh, but if you have both death rune mastery and BotN you're not just avoiding the it/ps refresh, but you're also avoiding the super weak blood strikes as well -- there's no bloodstrikes in the rotation beyond the initial setup at all at all -- just a lot of obliterates.
I'm usually a tank so only the hodir attempts are relevant ( not the best fight for this sort of think i know -- Hoping to get a deconstructor parse for reference next week ). It's important because there's a standard unholy dk there for reference.
Given how the SoA seems to be working on the PTR right now ( full application to the off hand strike ) I'm thinking that a very similiar build: