That's what uber content is like in Luclin. We never run out of mana. Tanks rarely die. If the guild had a combined health bar, it would fluctuate between 99% and 100% from start to finish.
If every ubermob in Luclin were to suddenly double in hit points...we could still kill every one of them. This was not true in the original game, nor was it true in Kunark. Mobs back then had high regen. They did high damage. People died, and there wasn't time to res them back in. Mana ran out. The guild hit point bar decreased as we fought the mob, and if our bar decreased slower than the mobs', we won. If it didn't, we lost.
Modern fights are no longer a race. It's not that fights are longer: a long race can be just as interesting as a short race. It's that there isn't any race at all. Mob hp drops, but guild hp does not. Fights are no longer real battles, they're a test of error control. Unless the guild makes a mistake, they will win. If they do make a mistake...they might still win, but it's possible to fail.
Failure is thus not a measure of guild power, or even guild tactics, it's a measure of guild perfection.
We don't often make mistakes. We very rarely lose. And it's boring, very boring. As long as we have enough clerics to do the rotation, and one magician and a few warriors, we can kill pretty much anything. All the other people on raids, the rogues, the wizards, the rangers....all they do is make the fight go faster.
It's tough to say what signs developers should look for, to see if people are having fun in a given encounter, but "melees going AFK" is probably not a good one.