Ok, this a way out there idea, so i know you will all probably hate it, 
What if USSR and US become Allies, and Japan and Germany become Axis?
Could it work? was pointed out, and i forgot, that in WT(yes i know this is not WT yet)you can go into battles with mixed teams?
Would make the MM numbers not spread out?
more people v people games?
mixed maps in rotation,
that a survey has been done to find fix, maps that people wont play?
I mean, japs in normandy aren’t much more crazy than KT in tunesia as some already propose.
I watched a film, little while ago
was about a couple Asian fellows, who ended up in German army, then in USSR army 
there was something along those lines in H&G, but it ended up being 1vs1vs1.
Was good on paper, but they diluted the amount of players per side in the match (because of players limits…)
Don’t mash them together, just combine the damn queues. Or force “play for every side” on for everyone and give universal XP
Why is it so hard
Personally I just want balanced matches, not sad stomps