I'd call pld my main role and I enjoy it. but in many cases I find people just don't play cooperatively.

if I pull a group of 5-6 mobs then for whatever reason I find many dps will make a deliberate attempt to find that one mob in the pack that I have the lowest enmity on and then do everything they can to pull hate and then proceed to rage at me for losing it.

if however they played cooperatively they would focus there attacks on the mobs I had the strongest enmity on and kill them first and thus I'd maintain threat on everything much easier.
second to this is the number of dps especially blms that for some reason refuse to use quelling strikes or even stop dps for a minute to let a tank get control of a fight.

see this in wod for example where dps will open really heavy bosses will go ballistic and then everyone rages at the tanks for not having hate but they aren't doing anything at all to help the tank get control.

so yeah I can see why people hate playing tanks in duty finder and in many cases I feel that the player mentality only hurts themselves. they wait ages for queues because there's a shortage of tanks, then they do everything they can to give tanks a hard time, then less people play tanks in duty finder and that means the quesues are even longer.

if players on the whole played more cooperatively then more people might be willing to tank duty finder groups and that would in turn mean shorter queues for everyone.