Skrugga works quite well with chief, because you can actually tank for the horde a bit, and stay alive while they overrun people (other than shield dedicant paladins who will shield riposte all the weak ones to death very quickly).

Also, the ability to take the extra dex edge helps with some of your other skills, from what I can tell (I seemed to cheapshot more).

I found cower worked very nicely for me. Staff defense was bleh. Take cover was unreliable even when perfected.

Generally though, I found that the staying alive longer enabled me to survive to successfully land things like spinebreaker (especially once I took that edge).

Dirty fighting had some useful effects (like blinding the opponent) and the weakened parting blow.