I think the unified merged matchmaking should be implemented FIRST BEFORE any overhauls like tech tree and BR. There has been so much debate about BRs, historical accuracy, etc and it is very complicated and contested. I think too much radical changes at once will not be good
With merged matchmaking there will be no more individual campaign playlists, when you click play you get sent anywhere. Berlin, Normandy, Pacific, and so on and so fourth. Theoretically it should keep as many human players together as possible
If anything I think it is more important that we see how completely full matches go. I have seen some here echo fears that the game will get even more sweatier than its ever been before.
I think it would be better to see how truly full matches play, then we can take it from there.
To be clear I mean campaigns would remain in that All their content is locked, just that there would be no more individual matchmaking servers for campaigns. Click play and it cycles through the campaigns