- Your parry is too low compared to your dodge. Because of Hold the Line you get much more out of parry. As more mastery you have the better parry gets. (You have to compare the ratings not actual percentage to reduce diminishing returns, but parry can be at least 1.5 times higher than dodge.)
- Your mastery is lower than I would expect for your item-lvl.
- Never reforge mastery to something else. Never.
- Do something with the free tinker slot.
- I'm not sure if you already are trying heroic content, but at least if you do not, mastery should be present a lot more with your gems. For everything where you don't have to fear quite high amounts of single hits, mastery is better. That's true for normal modes. And even if you are doing heroic versions, mastery is still very good. So if you need more stamina there, elexier/flasks and trinkets should be moved to more stamia first and gems, last. But you are the only one to know how much stamina you actually need.
Single item comments:
Head: I don't know much about ingeneered stuff, but if there is a parry-tinkering use this instead of the dodge one.
Neck: reforge dodge -> parry
Shoulder: undo the reforging, think about stam+mastery-gem (if you know that you need the stamina for heroic versions, you are fine)
Back: maybe reforge dodge -> parry, do some tinkering
Chest: gems and enchant are very stamina focussed, maybe go somewhat more to mastery; you would get more mastery out of the reforging if you would reforge parry->mastery (while losing some combat table coverage, but difference is huge enough to matter) - btw why don't you have the t11 one? it should be the first thing to get for JPs
Wrists: undo the reforging
Hands: undo the reforging, gems are again very stamina focussed
Waist: reforge dodge -> parry, gems are again very stamina focussed (why are you using a mixed one in the prismatic slot, normaly you use the stat you want to increase the most - either mastery or stamina)
Legs: reforge dodge -> parry, gems are again very stamina focussed
Feet: undo reforging, gems again very stamina focussed
1. ring: dodge -> mastery would give you more mastery (but with reduced combat table coverage, again, difference is big enough to do the change)
2. ring: reforge dodg -> mastery - btw: why don't you have the JP one? It's best in slot, too
1. trinket: I personally don't like this trinket much
2. trinket: never ever reforge away from mastery. Don't do it. No. Redo the reforging. Now.
Shield: maybe reforge hit-> parry
Ranged: maybe reforge expertise -> parry
I've recommended a lot changes from dodge over to parry. Maybe it's too much. Start with the big changes and see how long you are fine with them. I would greatly recommend to do this with a tool like http://elitistjerks.com/rawr.php, or a spreadsheet. You should be able to see where to stop going for more parry, there (just look at the stats-comparisons while moving points over).
I've also mentiond a lot of gems that could be moved over to mastery. I would greatly recomment to do this, as long as you don't need it. Since you may need the stamina on the heroic encounters, you maybe don't want to do it, now, if you are starting to work on them. However, monitor your health-bars. If you see that you are not in danger of "instant deaths" switching some of them over to mastery may be helpfull, even there. But only you can answer that. Many tanks switched over from mastery to stamina gems for heroic modes because of the much bigger single hits.
Talents: You probably don't use Gag Order much - Deep Wounds is the best single target threat talent we have access to. Maybe you want to switch over those points there. (Same for the one point in Thunderstruck. Just one point there should not be optimal in any case.)