In BC, for my guild at least, we considered the best measures of a tank to be A) how much threat they generated, B) How "on top of things" they were (positioned the fights properly, knew what they were supposed to do and when and actually did it then, etc), and C) How well geared they were.

B) and C) largely ran together as they tended to be a function of overall preparation. If someone has done their farming enough to always have the right food/flask/etc and knew the fights, they were probably thorough enough to have a bunch of badge gear at the very least. Generally you only had a departure between B) and C) if the tank was someone's alt/new co-main or a friend of someone who seemed capable but was really new.

A lot of the differentiating value of a tank came down to A) Threat generation. I know plenty of well geared tanks who were good people, punctual, prepared, etc, but for whatever reason couldn't threat their way out of a paper bag. Sure, the world needs OTs too, but how someone could get to t6 content (where we are) and still be languishing at 600-700 tps most of the time is beyond me.

With the arrival of The Patch, tank threat has blasted off on a rocket and pretty much everyone can now hold threat under virtually all situations by just face-rolling their keyboard.

So, my question is: how are guilds planning on evaluating their tanks now? Sure, quick reflexes and overall preparation are still valuable, but what's the distinguishing characteristic now? My suspicion is that it'll come down to dps (seems odd to be judging tanks on that, but you'd take a rogue who did 200 dps more than another rogue, right? If two tanks can both hold threat and have reasonably comparable mitigation, wouldn't you take the one who did more dps?).

Alternatively, I'm not in beta, so perhaps dps eventually starts catching up to threat somewhere around t8 just like it did in BC and threat starts being an issue again.

Regardless, I'm interested to hear how guilds are adjusting their evaluation of what separates a good tank from a mediocre one in this brave new world.

Consistency, just like your healers. The vast majority of tank problems are people quitting or not showing up frequently and so forth. DPS is fairly replaceable (actually, much more so now). Healers are kind of replaceable, but I still value their consistency more than almost anything.

If they get the job done, they're a good tank.