Tanks should 90% of the time (as long as a dps doesn't overgear them grossly) be top dps on those fast trash dungeon pulls or those giant vengeance-heavy pulls.
As for the healer being second. Take that as a hint of "YOU ARE PULLING FAR TOO SLOW". It means that the healer has time to stand and turret into a target without having to heal you. Do not let that happen. This is the reason I hate queueing as a healer. It is terrible when your tank decides to just pull a mob at a time.
DPS does not make a dungeon slow to clear. It is mostly on the tank.
Either way OP - if you have the time to post about an issue like this on mmo-champ you have time to check out your class as well. How about you take up the challenge and begin carrying the groups through dungeons?