Rune section: You need to include Runic Power as your 4th pool, especially for tanking. Rune Strike consumes RP at a pretty rapid pace, so it needs to be considered along-side runes as opposed to a different resource.
Also, the first rune in each set is on a 10 second CD. The second rune of each set is on an 8.5 second CD. (so B10, B8.5, F10, F8.5, U10, U8.5) This is for latency purposes, those with higher latency will still see it as a nigh-10 second CD, but those with little latency will have more benefit and can adjust their rotation accordingly. It may be adjusted on live to be a static 10 second cooldown for all runes.
Correction:
Unholy Command x/2
Reduces the cooldown of your Death Grip ability by 5/10 sec.
Lowers your cooldown on Death Grip.
(Does not lower the CD of Dark Command, which is the second taunt on an 8 sec CD.)
I would also recommend changing your Unholy DPS rotation to have PS > IT > BS > SS > UB, then start in with the SS spam. This will get all diseases up (the Glyph of Scourge Strike only has a 25% chance to apply the diseases, meh) so your attacks do more overall damage.
Just commenting for clarification so you can adjust your post. I'll delete this post once adjustments are made.
I did mention runic power in passing. However, I mention it as a filler use due to the fact that most tanks will want to keep up blade barrier. So runic power tends to take a back seat to rune usage. However, that being said rune strike is a nice ability.
Blade Barrier is awesome, but while it's up Rune Strike starts becoming the huge RP dump. It's hard to just sit on RP "just in case" for the wtf buttons when you're using RS to help push out the threat. I think a lot of new DKs will have issues with their mitigation until they realize the sheer amount of RP it consumes.
haha thank you sir... i think i fleshed out that part a lot more than I did in the past few months. When you've played death knight for a while i guess it's just natural and overlooked.