If that's the case, the whole "adventurer in need" thing is pointless in the first place, and no amount of "balance" would change anything.
The thing is, if I get nice rewards, I'd queue up - but I don't. Same rule should apply to about every healer/tank that is not going.
So once it reaches "adventurer in need - DPS - here get some clusters and other rewards!" I'd totally hop on and queue up for trial/dungeon/5060.
Right now, I don't. If I were a tank, I would do the same thing. What's the point in doing DR other than leveling an alt right now?
The rewards need to outshine the potential horrible group you get from pugging DRs.