Just wanted to make sure I am on the right track and see if there is anything I should change in terms of gems/reforging/spec etc. I've been told I'm a bit squishier than other tanks in heroics.
You are probably quite squishy.
Start with concentrating much more on mastery. Get items with it, reforge for it, gem for it.
Don't do anything to up your expertise and or hit. On the contrary: Reforge them to mastery and if that is not possible reforge them to dodge/parry. You don't need them, at least not if they are as low as your's anyway. Your problem is survivability, not threat. Taunt does not miss anymore, so you just can taunt a mob back, if someone should overtake you in threat during the first view seconds. Later on Vengeance should be so high, that you should be easily before everybody else.
Stamina is also less important. If you have survival issues it's less helpfull than more avoidance or block. Stamina is only usefull for surviving few big hits before the healer can land the right heal. We don't have such a dmg-pattern in Cata. But big/fast heals are expensive. And heals are small, anyway. So it helps much more if you reduce the dmg the healers have to heal up again. You will seldom be healed to full, anyway. So the additional health does not help you for most of the encounter, anyway.
So what should you do in detail:
Get better items. Items should be valued in the following priority (a slight increase in item-lvl is not worth it, if you have to move down one category):
1. items with mastery + dodge/parry
2. items with mastery + hit/expertise or items with dodge + parry
3. items dodge/parry + hit/expertise
4. items with mastery + crit/haste
5. other items (you probably need one of those for your ranged slot)
6. items with resilience
Reforge them to mastery and balanced avoidance. It's cheap. Do it.
- Items without mastery should be reforged to mastery:
- items with dodge + parry: reforge the higher one to mastery
- else: reforge the highest of hit/expertise/crit/haste to mastery
- Items with mastery should be reforged to dodge/parry:
Both should be relatively close together, with parry beeing slightly higher than dodge.
Think about geming for mastery:
blue: stam/mastery, yellow: mastery, red: parry/mastery
There is one goal you should try to reach: A combined block + parry + dodge of 72.4%. If you get this, your Shield Block changes to a quite good CD 1/3 on the time. Because if you pop it, you will not get hit by any normal hit. Every hit is at least blocked, so reduced by 30%!
Redo your talents; If you put 7 points into arms, 2 of them should go into Deep Wounds. (Not for survivability but for more dmg/threat.) Think about if you ever use Blitz. If you don't need it, take those points.
Think about using Intimidating Shout Glyph instead of Commanding Shout. It gives you a safe second "stun like" Button every 2m.