EU+US Brewmaster, Prot Warrior, Prot Pally...

[Lebowski]

Are any of the tank specs even remotely viable in BGs? i.e. Are any of them better at flag carrying than other specs, put out any sort of decent damage, mitigate damage well enough to hold nodes longer than other specs, or generally bring anything more to the table than other typical specs you see in this bracket?

 

[Flaxy]

Resto Druid is best FC. BM is the only tank that does "ok" damage

 

[icehawk]

I can only speak for Prot Warriors as that's the only tank class I play from time to time in this bracket. They don't make good FC's as they have no damage mitigation nor heals (you have to kill something to get the heal!). They are a fun class to play but only if you team up with others. They have good utility with a slow, 2 x charges and a ranged stun talent but damn, the dps outright sux. You won't find yourself killing much but if you are teamed up with say another dps or 2 you will have some fun. You can keep a target slowed and stunned while your teamies whoop with their dps.

But in answer you your OP, in reality Prot Warrior is fun to play (well at least with others) but it's not viable in iPvP, especially if you solo queue which I mainly do.

Can't speak about the other tank classes.