This is a map I would someday like to see. One that contains all major theatres of the war.
Normally we favor small maps but this one would have to be large. It would also have to be less detailed and way out of scale. You would also have to skew things to get the major countries more or less covered.
For geographic accuracy it would be an abomination.
It would also require a lot of custom tile work to get different vegetation types and such on the same map.
It's possible to build a 30K wall to separate east and west and with a wind downdraft at 28k or so, no one would be able to fly a zero over Germany.
With something like this we could offer more planes at the same time but keep them in battle against their historical adversaries.
It would be even better if we had a 4th country, rooks vs bish in the east and knights vs pawns in the west. That way you would know from the roster who was playing where but without that I guess you would have to look for radar and base flashing to know where the action was.
We could also run a timeline event that encompasses the war as a whole.
It would be a huge effort to build it and I don't have the necessary skills, but maybe someday