Possible fixes:
Remove unranked mode → you can play custom game
or
What I would prefer more:
match ranked vs ranked players only
match unranked vs unranked players only
Reasons why unranked players should not be mixed with ranked players:
I understand that some players need a few unranked games to warm up before they start a ranked game - that is ok
or you can test some strategies - that is ok
or you can just do nothing, preteding to be afk, team kill your allies and ruin someones ranked game nice troll, great fun - definitively is not ok
Why are we ranked players who play teams forced to play with unranked players who do not play serious enough to play ranked mode?
This is why I suggest:
match ranked vs ranked players only
match unranked vs unranked players only
Ranked and Unranked MMR
There should not be difference between ranked and unranked MMR it should be the same for both modes.
Ranked game:
My MMR in 2v2 random is around 4680. Enemy average MMR is around lets say: 4500
Unranked game:
Unranked MMR is hidden and is separate from your ranked MMR. It can be the same or higher or lower than your ranked MMR.
There are players that their unranked MMR is much higher or more lower than their ranked MMR.
After unranked game:
I checked the opponents MMR after the game: 3600 and 3618 and calculated the average MMR 3609.
I also checked ally MMR 3641 and (my ranked MMR is 4680) our average MMR 4160.
3609 - 4160 = 551 MMR average difference
Sometimes the difference between the averages is +/-500 or even +/-1000 MMR.
Maybe my unranked MMR is more lower and then the differece is not 551 MMR but only 100 MMR I do not know.
This is also why ranked and unranked MMR should the same.
If you play unranked game it should be always based on your current ranked MMR. But unranked MMR will not effect your ranked MMR.
Ladder 1v1 and Teams
https://us.forums.blizzard.com/en/sc2/t/ladder-1v1-and-team-games/10493
Balance and a few things
https://us.forums.blizzard.com/en/sc2/t/balance-and-afew-things/10592