I will probably be building a heavy EH set to deal with fights like Rotface and Marrowgar, where large amounts of physical damage is the primary issue. This will be constructed out of badge and crafted gear. There's almost an entire plus armor set available. The chest, gloves, belt, and cloak from badges, and crafted pants. The chestpiece alone has more armor than any of the mages in my guild. Think about that, the mitigation you'll get from these pieces is the equivalent of having whole clothies strapped to you for protection. The gear, however, is not without its flaws. The high stam/high armor gear has almost no avoidance on it, and most of it is parry, which hits diminishing returns like Manny Pacquiao, hard and fast. It will be helpful on some fights, but in others, it will become a liability.
Then there's the T10 set. It's well balanced with regards to dodge and parry, and is possessed with a DR free boost to avoidance in the four piece set. This will be particularly powerful in the Deathbringer Saurfang encounter, where higher avoidance can allow the raid to avoid high amounts of damage late in the encounter when Marks begin to overwhelm the raid.
I'm also considering the usefulness of a Hodir style Frost Resist set for Sindragosa, however, I'm unsure of how much damage the tank will actually take from frost, as opposed to the melee. There's also the possibility of an Anub style block set for Lady Deathwhisper and Ogrim's Hammer, but the gap in the attack table due to Chill might make that untenable. Throw in a ret set of gear, and I have no bag space left... :(
All in all, my general progression set will probably be a combination of T10, along with Off set +armor pieces, along with dual stamina trinkets. But the diversity of the pieces allows us to customize our gear set for the encounters we struggle with, and this is a welcome change from previous tiers.