It is fine to have multiple progress trees, but trapping each tree on a specific mapset is unhealthy for the game, as some have pointed out. I believe there are possible fixes which would still cause minimal harm to historical accuracy.
The game might be healthier if players were able to queue their chosen squads for any campaign. Some restrictions could be placed on them, like swapping their weapons for campaign-appropriate low-tier equivalents (smg for assault, etc etc) for that match only. That would give people some XP and access to their “alt campaigns,” as well as encourage leveling more stuff.
This is just an idea/example to suggest that it’s possible to fix this, without breaking much else.
A bit confused by what yo mean, but it looks like a variant of having 1 xp barrel, mainly for the axis, since they will have access (sic) to all the campaigns?
My idea is, each campaign has its own squads and unlocks, but those squads and unlocks would be available for use on every campaign.
For example, I would be able to use my Moscow Russians to storm Normandy, but their weapons would be temporarily switched for non-upgraded Normandy equivalents. And their uniforms, obviously.
This way, I would be able to level my (for example) Moscow-Russian flamethrower squad on Normandy, but I would get Normandy campaign progress for that match. And if I want access to upgraded Normandy weapons, I have to level the appropriate Normandy squads.
The main advantage of this, is that players would be able to queue for any map without abandoning their progress. Instead of having 1 playerbase per campaign, we’d have one big one.
I don’t think my idea is perfect. I would personally prefer a version where all weapons are technically available for all maps, but I understand that the historical-ness of the game would suffer a bit from this.