I think that game need to, at least temporally, change the way characters for causal queue are selected. Reason is that low player-base means that often players with vastly different skill are matched against. Sure, in causal queue you can select ‘similar skill players only’, but then you rarely get a game. I believe that more even matches could be achieved simply if same two players would just play different characters. With my best characters, I can play against master level players and snatch few rounds here and there. With my worst characters, I can play quite new players without holding back and have few round or even games taken form me. I assume similar thing applies to everyone.
One possible solution is that you would select character after match is made. You would do same blind selection of character as now, but after you know who you play against, what is their player level and rank.
Another possible solution is that current hidden causal rating by would be separate for each character (if it is not already), and players in causal queue could join queue with multiple characters if they want. After mach is made, server would itself chose most balanced match-up among selected characters of both players.
Moments before writing this, I have entered queue with what I consider my third best character, got matched three times against players with <5h playtime and easily won. Then I switched to my third worst, so that I can play them more evenly, but got twice matched against ptrsdboy and got completely obliterated. Neither of those games I assume was much fun for anyone involved, but In my experience I know that they would be very interesting if I could swap the characters I played it them.
I understand drawbacks of solutions I propose and I think that current system is generally good, but it needs decent player-base. This will help to make causal queue more fun for people in meanwhile.