Also, Y U NO DROP RINGS AND TRINKET H.DS!?
Gemming and reforging looks solid. Work on replacing your rare quality gems with epics. Spec and glyphs are on the money. Get some rings and a trinket!
Waiting on my last 4 (4.5 if you count the tier shoulders as a sidegrade) items from BIS, will upgrade gems as I get full BIS -.-'. Blasted things will never drop.
You're full BIS, but your Parry:Dodge ratio is about 1:1 when it should be about 1.15:1 (see http://img835.imageshack.us/img835/118/graph3t.jpg and extrapolate the black line to about 5000 on the x-axis gets you to about 1.15 - you're the black line because you have 4000 mastery) because of Hold The Line. This is actually an extremely negligible (in current gear, it wasn't negligible back a tier or two), on-average type of gain, but I'm nitpicky. To save you the math, that puts your parry at ~2693 rating and your dodge at ~2341 rating. This is completely based off of your armory, though, and not including buffs. For raid-buffed, add in raid-buffed ratings and solve this system of equations with wolframalpha: (p/d=[1.15 to 1.17 ish based on my extrapolation], p+d = [your total avoidance ratings combined, in this case 5034]) The graph is still fairly accurate despite you having 4k more armor than that base warrior.
So, all in all, geeming seems fine, I'd personally go a little bit more stam because of wasted mastery (except when shield block is active - warrior mastery doesn't convert excess block into crit block unless Shield Block is active, so you have a theoretical 67% time where a lot of mastery is half-wasted), and for the same reason I'd also drop Soulshifter Vortex, even though its stam is good, for Resolve or something else... but the stam gemming is really personal preference, and since impale is the only thing to worry about with post-nerf heroic DS I would personally go for that. But that's just me, if it works for you as-is then great.
Overall 8.5/10 - 9/10
I'm not really in a position to judge quality of DK gearing. Esp. not at the level of theorycraft that would be required to nit pick what looks to me like a pretty good setup. :)
I do have an honest question though. Why did you take leather-working? Just for fun or...?
@Alpheen: Yeah, I've been (slowly) swapping out Mastery for Stam as my gear has been slowly improving. I was thinking about going with Exp/Hit instead because I don't really do any raiding and it's pretty nice in 5 man instances, but most of my healer friends are a little shaky in the gear department and I'd prefer to make their lives a bit easier. :)
LW because of the stam to bracers, was at one time the only real viable bracer enchant for DPS (BIS profession for DPS at one point by miles, now it's just equally-competitive [or close]) and the stam was really nice for progression, since no real stamina enchant exists for the bracer slot. I also preferred the stam to bracers over any other gain for the slot for tanking, as well as no other real profession bonuses (to any slot) seemed as competitive in my eyes for tanking (and dps). The stam enchant is a fairly large amount of stamina, and stamina's always been an amazing stat for progression, especially if your healers are disciplined and don't have mana issues (like mine were all throughout cata, they had 0 problems even in t11, so I stacked stam until mastery became more viable [or should I say reliable])