As for the issue with duos, 2 man group do have longer queues, but this is sorted by asking for 1 random from the chat channels. The queues are much shorter this way. (2-3 minutes).
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Anyway, I got Lucio to level 5 but it's been tough going in QM (I am 2-6 on him) with lots of wonky comps. (Abathur with no other specialist or frontline, or up against double spec split push comps)