It's the same deal when going from a three tank fight to a two tank fight. Or 7 healers to 6 or 3 to 2. Or just being a DPS. Sometimes you sit for your guild to succeed. That's not asking much. Just hop in next week.
Or... be remotely decent at your offspec and rock out!
It's actually not the same.
When a raid drops from 3 tanks to 2 or 2 tanks to 1, ideally they'll have the tank with the best offspec to go dps. That way if you have a lot of plate or leather drop, you can chose the tank to dps based on that.
But instead, we have two tank classes excelling at the fight to the point that you have guilds making decisions on who goes dps/benched based on the class they're playing and if the tank is unlucky to not get a dps set because there isn't enough loot to go around, they just get benched.
While you two may not see it as a problem as both of your classes are at the top of said fight, it is a problem when tanks tend to be the top damage dealer on that fight and the difference between tanks can be as much as an entire another dps player or more.
yes .. it is the same. It's heroic. You are always going to pick the best comp available within your raid (unless you are .. you know .. dumb).
This fight we have our pally tank because I have by far the most OP aoe as dps from all of us 3 (dk, pally, monk). So it's a better dps gain if I go dps compared to him going ret.
On heroic spirit kings the pally goes dps because I can cheese the fight as a monk tank and soak the 1st boss cleave by myself.
On H vizier the DK goes dps because me and the pally are better to tank that fight.
On Lei shi the pally goes dps because me and the DK have better tools for that fight.
Welcome to heroic raiding .. you use the best comp available. It's been like that since .. forever.
And fights that require less tanks than usual, usually are not tunned to be dps checks. This is one of them. Our DK is spamming icy touch to dispel quickening from the boss, and we still beat the boss with minutes spare on the enrage timer.
You are making a drama about 1 fight in the most balanced tier we had so far. This is the only tier I can recall that all tanks are getting equivalent moments to shine. You pick tanks based on minor details, but every fight is perfectly doable with all tanks.
It's not remotely close to situations we had until this point.
Or you were not around during Firelands were DKs were benched every fight, or Dragon Soul were DKs were better at every single fight? Or maybe wotlk where paladins dominated ICC and warriors were left in the dust? Or perhaps Ulduar that DKs were gods, and nobody in their right mind allowed paladins to tank fights over any other tank?