1,000 times yes to this.
Would be so much easier...say when i'm trying to coop with a certain demon...not to have to deal with full queues. Also would allow smaller players to prevent match ups with way larger players. Sorry, i don't care how much "boost" you give, a 400 AP army next to a 2.6K AP army is mostly going to be the smaller player either hiding, dying quickly or feeding off scraps and frankly isn't really fun for either party involved. Coop queues or tiers that segregate out would be a very welcome addition.