I suggest you read up on the Effective Health theory. In a nutshell, it states that your effective health is the amount of raw damage it will take to kill you if you do not avoid any attacks or recieve any heals. Effective health is a function of your maximum health and armour.
Gearing for maximum effective health for progression raids gives your healers a larger margin to handle spike damage (specials, or if you miss a shield block and get crushed for example) without wasting their mana, as in 25 man raids your healers will be pretty much constantly casting heals on you, regardless of whether you avoid an attack or not.
Looking at your gear, you're at the point where you can just stick +12 stam gems in everything. Generally socket bonuses are not worth losing the stats you'd gain by using a better choice of gems. The only exception to this that I can think of is [item]Tankatronic Goggles[/item], where you can use a stam/def gem and still get the same amount as stamina as just using a +12 gem.
By the way, welcome to Tankspot =)