Here's an idea, maybe tanks and healers get unlimited leveling roulette bonuses, rather than just the single daily one. Once I've done the leveling roulette and the 50-60 one, that's pretty much all the meaningful playtime my tank gets for the day. This is what's making leveling my first tank so slow, since I'm not overly fond of PotD.
That way, more tanks and healer could potentially be in the queue.
