Another thing i feel i should mention about your post

"I don’t even own a warrior, but I’ve heard enough bitching from both sides to recognize what makes a good one"

Easy to judge people when you havent even been in their shoes right? Have you ever even tanked before?
Having heard arguments from both sides doesnt make you a better judge of talent... theres alot of things that go into being a tank that you really dont understand until you have played one. (well for most people anyway)

The most important cooldowns for tank range from 8 min (last stand(warrior)) to 1hr (Lay on Hands(paladin)) (note that shield wall is on a 30 min cooldown) which is why tanks have a hard time deciding when it is ABSOLUTELY necessary to use these abilities.

Most Good tanks make use of it at the right time but i am 100% sure that those tanks have also used them when they really didnt need to, wasting it before they actually needed it becaus ethey thought they had no choice.

Your perspective on tanks seems to be very limited. Most issues (i'd say 99% of the time) on trash when aggro drop is not part of the equation, is because of some over zealous dpser who thinks he/she knows everything about tanking and isnt smart enough to pay attention to their own threat/omen.

A good tank can call out when a dpser threat spikes but in the end the person who should really be paying attention to that is the Dpser themselves, it's not really the Tanks responsibility to make sure that the dpser is paying attention to their own threat.

Dps Threat scales, Tanks threat doesnt scale that well and it's designed that way intentionally.

Basically from your explantion of a good tank they are the ones doing everything well everyone is just sitting back and enjoying themselves. It's explanation like yours and the mentality like that that causes Tanks to go through the Burnouts they experience... you think it is a coincidence that Tanks have the highest burnout rate when the majority of people think the way you do?

It's easy to say good tank should do this and that when in fact it has nothing to do with being a tank in the first place(most of it anyway)...it's about being a skilled player, anyone can make those callouts etc

It's really unfair to expect the tank to:
1) Pay attention to his threat as well as the dpsers
2) Pay attention to all the mobs around him and check if they are running to a dpser because a) they over aggroed b) broke cc c) didnt follow the kill order the only person i think a tank should watch out for is a healer...that is it
3) Paying attention to all their Global cooldowns, while trying to maintain their highest threat rotation
4) Calling out everything on Vent
5) etc etc tec

They arent the only ones in the raid god forbid someone else take on some of the responsibility for stuff going on... i mean it just easier to sit back and let someone else do it...especially someone who already has one of the if not the most important role which encompasses alof of things to pay attention to already.