Please keep the discussion constructive.
Also BR systems make it hard if not impossible to add other armies like france for example.
Since a french campaign would be very cool but with tech trees basically impossible since you’d have basically nothing for them past rank 2. Unless you have unique french stuff up to rank 2 and then all the way to high ranks only US stuff and captured german/italian stuff.
The current campaign system allows you do add early war factions without having to worry about the rest of the game and making it more or less equal by limiting certain vehicles and equipment.