So I was wondering if I'm gearing myself too much on stam. I currently have 28k hp on the dot, ~23k armor, 21.3% dodge, 16.54% parry, and 21.01% block, def capped. I have mostly all gear from heroics except the CoT shield (which still hasn't dropped after 15 runs) and the Sword of Courage from UP.
I'm mostly running 10 man naxx, 10 man obsidian sanctum and randomly joining 25 man obsidian sanctum, 25 man vault and 10 man vault runs. I've been the OT on my guild runs as the guild druid has almost hit the mitigation cap (he's hovering around 74%) and I've been MT on pug runs.
My question is this: should I gear more towards damage now or still try to get more avoidance and/or stam? I would like to gear myself of all 10 man content and some 25 man (I don't have the time to play enough to join a guild that runs 25 man's, I'm more of a "casual" player... yay grad school).
What is your endgame goal? Are you going to be MT/OT 25 man Naxx/Sarth, going onto Malygos, or just going to stick to 10 mans?
Your gear looks fine for tanking all the 10 mans, probably even Malygos with a few upgrades from Naxx. You probably could start working on your threat stats, such as expertise and hit, although you will get plenty of each with upgrades from Naxx, etc.
I would make the following suggestions though:
A new weapon and shield would probably be your biggest upgrade, but it looks like you already realize this. The sword from UP and shield from COT are very decent alternatives, there is also a sword and shield in 10 man Naxx, the Shield of Ruin and Slayer of the Lifeless, which are also decent alternatives.
Get an Armoured Plated Combat Shotgun crafted and gemmed with 24 stam. You won't replace it with current content, and unless they have a new crafted gun or a drop from Ulduar, you probably won't replace it for a very long time.
Use your next 25 Heroism Emblems on a Chained Military Gorget, its a very nice tanking neck that provides both avoidance and threat stats, along with a ton of stam.
Work on your Sons of Hodir rep for the shoulder enchants. Even though they provide only avoidance stats, it will allow you more freedom in the rest of your gear. The quest chain to access the dailies for Sons of Hodir starts with a quest in K3, "They Took our Men!"
Once you get an epic cloak, I recommend enchanting it with 16 defense if you need it, or possibly 22 agility if you already have plenty of defense.
I believe 22 defense is currently the best enchant for chest in terms of item budget, but you could also go 10 stats or 275 HP as well.
Enchant your bracers with +15 expertise, imo, its currently the best bracer enchant until you reach the expertise cap. They are bringing in a new stamina enchant for bracer in the next patch, if I'm not mistaken.
Enchant your gloves with Armsman, +2% threat and 10 parry
Get a belt buckle for your belt, and put a 24 stam gem in it (You might already have this, I don't think armoury displays the belt buckle or the BS-only bracer and glove sockets)
Pants are fine
Get 22 stam on your boots, its a very cheap enchant. Once you get some epic boots, consider putting Tuskarr's Vitality on them, 15 stam and minor run speed.