Well you're partially in wrong gear I presume due to the current fury spec, obviously you logged or were on there out of your full gear set, but you still have a few items on while in that........and u gemming for parry. Dont.
Gem for defence if you need it but otherwise better to use dodge + stam than parry because more diminishing returns. Also in the prismatic you get more back out of the 24 stam gem unless you really need to stack in defence (shouldnt need to if you doing ulduar). And if the socked bonuses arent very good usually more worthwhile to stack in the 24 stam gems anyway.
Couldnt say more till I see more of the gear. As for spec not that up on warrior specs.
Well having a look you seem to be very much threat gemmed, defence you got a lot of wiggle room too.
Do you find major issues with threat? Because generally Hodir ulduar wise is the only one I'd expect that (which you dps as?) and Naxx you're geared enough to be ok, ulduar is far more about survival as things hit hard.
In terms of what the best return per investment, the 8 exp +8 hit gems are low comparative value if you need to make socket bonuses compared to 8 def 12 stam or if u need the threat 8 hit 12 stam, and in the prismatic belt slot the 24 stam is better return. Personally I much prefer to gem for eh and avoidance, stacking stam where possible and adding dodge/defence with stam in the others when socket bonus is worth it.
For feet tuskarrs is recommended as while you lose a small amt of stamina, the big gain in runspeed can be wipe saving in a number of circumstances and can be very important for a tank. Also enchant wise with so much def to spare super health is probably the best enchant for you, but what you got is still solid so up to you really.