ORIGINAL: Helpless
Btw, anyone who disagrees with logic of withdrawals can always change it in editor. It is not hardcoded.
But in that case forces would just stay around, right? Well, you could create house rules to have at least so-and-so much CV and planes sitting at the western edge, and south-western edge of the map so mimick good old WiR. But it isn't as nice as the old and simple fronts.
Yesterday again I read in the history of "SS LAH" that Hitler had actually ordered the withdrawal of this division from Russia for reformation at training grounds "Sennelager" on February 21st 1942. However, fighting and demands in the Southern Army Group Sector required this division to stay around until late May that year before the withdrawal actually took place. Similary in 1944 it was planned to throw this division to France, but OKW convinced Hitler to send a more easily withdrawable unit instead.
With the static system you are implementing in the game, the whole situation on the eastern front is entirely ignored due to fixed withdrawal dates. No flexibility appears to be retained, and this approximation is much too crude as any withdrawal decision does clearly interact with the situation in the east as much as the situation elsewhere.
Clearly using house rules could work, but it would mean making a step back from WiR here and would seem very unsatisfying. It would surely deduce a bit from the price I would be willing to pay since it just switches out a couple pro's and con's between this game and WiR, which is free.