By Boss, These are the predicted number of tanks that are needed.
(According to my understanding)
Anub'Rekhan -Three Tanks
Faerlina - Three Tanks
Maexxna - One Tank
Noth - Three Tanks
Heigan - One Tank
Loatheb - One Tank
Razuvious - One-Two Tanks
Gothik - Two-Four Tanks
4HM - Two Tanks
Patchwerk - Three Tanks
Grobbulus - Two Tanks
Gluth - Two-Three Tanks
Thaddius - Two Tanks
Sapphiron - One Tank
Kel'Thuzad - Three-Four Tanks
Five One Tank Fights
Five Two Tank Fights
Five Three Tank Fights
What is a raid leader (or tank officer) to do? Switching members between each boss, with so many bosses, just isn't an option if Naxx is going to get done in any sort of timely fashion. And even if you do, you have to have enough tanks at the ready to perform on the three tank fights, while not having so many that it could take a month to get a tank in for a single tank fight.
I think LOKI's plan will be to run with three tanks - Two being more pure Protection, and a third being a more offensive/threat/OT type. We currently have three protection warriors, one protection paladin that's out with computer issues, and another protection paladin who is swapping over from holy.
I issued the following note to our tanks earlier today...
I'd just like to put it out there, that decisions regarding what Protection tanks are brought, may be influenced by their ability to DPS when not tanking, in order to justify a full three spots.
That's really what it comes to. It wouldn't be such a big issue if Dual-Spec's had been released yet, but they have not been.
Regardless, I would suggest that all tanks stay current on their DPS gear/rotations. Cozy up to a friendly neighborhood DPS warrior and pick their brain, gem and enchant your DPS gear as if your raid spot depended on it, and know what buttons to press when - because as long as there are bosses that only need one tank, you may find yourself scrambling to justify getting to stand behind the boss instead of outside the instance.