Well with respect, personally I beg to differ about the hit/exp part.
1) My opinion about hit/exp. Indeed DK's main surviving mechanics (Death Strike/Blood Shield) doesn't not require successful hit any more since hotfix in 4.3. However, I still recommend to build enough hit/exp. First of all, surely less misfire will make your resource regeneration smoother, which in the end makes your rotation smoother. Also more successful auto hit means more SoB which also gives you more self heal. However the most important reason, in my opinion, is that in MoP literally all tanks use hit/exp as primary stats except for DK, for all of them are much more resource-dependant than they used to be. That means, if a dk doesn't have enough hit/exp, he will most likely have threat problem against other tanks, especially bears and monks whose threat is as high as hell. Our group (unfortunately) has double dk tanks. I'm hit/exp capped and the other guy didn't care about them at first. I had to completely stop attacking even auto-attacking in order not to get aggro while he is tanking. Then I talked to him and he got some hit/exp. Now things are much better.
2) My suggestion about hit/exp: get 7.5% of both. I personally suggest to get 7.5% of both. Hit is just capped of course. But expertise is just soft capped, which is not dodgable but still parriable. Obviously as we know, our 2 main abilities, Death Strike (bypass parry) and Rune Strike (bypass parry/dodge/block) should now be guaranteed hit. As expertise goes higher, DK doesn't benefit too much about that (pretty much just melee and Heart Strike). However, FYI, I have 2 set of gears myself: straight tank set, and a hybrid "dps-tank" set. Tank set has 7.5% expertise, but "dps-tank" set goes higher, for those farm bosses to get more dps.
3) My suggestion about reforge: get hit/exp only from reforge. I recommend to choose gears have mastery on it, and reforge the other stat to get hit/exp to 7.5%. For those which do not have mastery, I still recommend hit/exp cap over mastery. This way you will lose around 1-2% parry/dodge, but hit/exp goes significantly higher. I don't think it's not worthwhile. I don't want to get hit/exp from enchant or gem. I'll explain in next part.
4) My suggestion about enchant/gem: Stamina>Mastery>parry/expertise. I do understand that theoretically mastery provides more damage reduction than stam. I even calculated to prove that myself. But it's just theoretically. Since 4.3 I found you will want as much stam as possible for those hard bosses (since you can't get it from reforge, I recommend to get hit/exp from reforge, and don't waste the source of stam from enchant/gem on hit/exp). There is much magic damage going as well as physical spikes. More health will always be better for those extreme situations. And I trust that for a skilled dk tank, several hundreds of mastery loss won't make that much difference, if he uses his abilities properly. Afterall there is always overhealing from healers which is more than enough to cover that little bit mastery loss.