I'm always in a queue (as a dps) for a dungeon while FATE grinding as it gives me the opportunity to practice my skills in a group environment, as well as picking up some loot for my lower level classes. If I were playing a tank or healer, I'd probably do 2-3 runs of each dungeon (except maybe Qarn or AV, because ugh) just for the practice.

I wish dungeons rewarded a bit more xp to offset the wait times for dps, but it sounds like the incentives for running dungeons in 2.1 may help with this.