All you people that downplay the difference in time between runs "if the dps is good" are missing the point. If a geared tank can't be bothered, whether through fear or laziness to play their job well enough to handle more than a single pack at a time (when they clearly have the potential to), then why should I as a dps be expected to put more effort into the dungeon than them?
If I get a good tank and healer who pull appropriately, then I'm inspired in turn to play seriously. I'll use cooldowns and the appropriate weapon skills and burn down mobs as fast as I can.
If my tank isn't gonna challenge himself, I won't either. I'll probably tune out, carry on a conversation in FC chat, and 1.2.3 instead. Fair is fair.