Another game uses the years of the war in blocks, the years and equipment getting better as the campaign goes on. For instance the campaign starts in '39 and '40 and the only airplanes and GVs you can use were the ones available in '39 and '40. It then goes on to '41 and '42, 43' and '44, and then 45 "all older equipment still being available in the later years of the war.
Why not try that here. Shut down the other two WW-2 arenas and go into, say, 3 day rotations of each block of equipment. Maybe not as an "all the time" thing but as an experiment and see how it goes. We have a lot of interesting early war stuff that hardly gets touched cause 95% of the action is in the LWA and most of that action is late war airframes. Its kind of a shame NOT having some of these historical correct combatants ever seeing much of each other.