I've been reading about Deep Wounds including tank specs, and decided to give it a try last night. I used this spec. EDIT: TS Posts which inspired me Here.
Patchwerk: I was the cursed middle health tank, whom takes the fewest hatefuls, and therefore has the least rage to play with. Still, I pulled 1730 DPS, 8% of (~32,000) which was Deep Wounds. For comparison, Revenge was 11%, Shield Slam was 22%, Damage Shield was 2%. Deep Wounds was enough to push me over the primary hateful strike tank's DPS, despite taking about only 70% of the damage he took, and getting revenge lit up far less.
Grobbulus: Was MTing him, and Deep Wounds was 9% of my Damage. (slightly more then Revenge).
Gluth: Was kiting Zombies, and it made up a decent amount of damage.
Thaddius: I was just DPSing on everything. Deep Wounds made up 17% of my damage, nearly toping Shield Slam at 18% !! This put me 1000 DPS higher (2900) then the other protection warrior who was doing the same job, but without deep wounds. I would imagine the big benefit came from getting high stacks of it while charged, then them being able to continue rolling while polarity shift running was going on.
Razuvious, Gothik, 4H, Noth: Nothing Exciting to report.
For an ability I didn't have to think about, it had great results. I can't imagine Cruelty providing that kind of results for 3 points. Deep Wounds also proc'ed off of Thunder Clap, adding some non-trivial bleed damage to AoE groups. I was using a fast weapon, Red Sword of Courage - but I may want to try a slower weapon (Broken Promice) and see if the increased Deep Wounds damage outpaces the reduced number of Heroic Strikes (and if it does, if the reduced rage consumption / increased rage availability is worth it)
What did I give up to go 18 points in Arms? The biggest cut was a point out of improved revenge. Losing Puncture and Imp. Shield Reflect didn't hurt at all, nor did going back to 0/5 Cruelty.
What else did I gain, besides Deep Wounds? Impale, mostly. My crits we're noticeably bigger. I also got an extra 10 rage on Charges and cheaper Heroic Strikes. I could have taken points out of Shield Spec to fund 2/2 Revenge, or some Cruelty if I was feeling really aggressive, but that felt a little too untankish.
Anyway - I think I'll continue to rock this build for a while. I'm happy with its damage/threat output, and I seem to be just as durable as I was before.