Long queue times for dps is an old myth that is perpetuated in most MMOs by people who are part of "i want instant everything otherwise its too long" generation.
The fact that there are more dps classes than tanks and healers is offset by the simple rule that most groups have at least twice the number of slots for dps. In fact, in large scale raids dps actually have lower queue times than tanks.
Tanks actually have fairly long queue times. I actually had a CT queue that was over 10 minutes the other night.
Queue times are fine and not as different as most people like to think once you stop buying into common misconceptions and start thinking like an individual.