I agree tanks get alot of flak. I think everyone should learn dps classes better so you can tell when a dps slacks or sucks that way everyone will get the same amount of flak. Its easy to find basic things like the blm blizzard spamming at full mp, an archer that does not keep his dots up, a drg that doesnt keep his heavy thrust up, or a monk thats not dancing around the side and back of the target. Just watching the buff or debuff bar for a little bit and you can tell which dps are slacking. Its easy to tell when the tank is slacking due to lack of aggro but a dps you actualy have to watch.
The few amazing tanks really spoil us dps. The game should really put more focus on teaching how important a tanks gear is. An under leveled weapon is a giant loss of threat even flash scales its threat on your weapon damage. That and a tank with proper gear can take the damage for the normal 3 mob pulls so you have your dps spread its dots and aoe among the targets to down it faster overall and a good tank can hold aoe threat, atleast from non blm. They made aoe attacks and dots have enough potency where just having 2 targets make it more total dps than focusing a single target. Even then a marked target is still nice for those single target attacks we have to do to keep our buffs up to do max aoe damage is on the target with the most threat.