If Dynamic Queue is here to stay why not just split the player pools when they're holding their matches?
Solos only queue with and against other solos.
Duos, three mans, and 5 mans go in the other pool, with 4 mans basically not existing.
Would this not solve the issue?
EDIT: Quepha made an interesting point, that 2's would get hosed under this system as duo's would only be able to play with trio's and vice versa, with duo's being much more common. I suppose then, you would need to allow duo's to get placed in both queues with priority on the 532 queue.