Back to france (before this thread explodes), please, once more:
I dont see why partially scripted troop-movement (aka historical battleplans enacted by the AI) is a pipe-dream, when it is quite obviously a much more simple solution than any convoluted or arbitary work around could ever be?
You wanna dish out advantages in the 1936 scenario that neither will enable germany to roll over france in 1937 (e.g. tech/doctrine advantages in the absence of practicals) nor will ever be out-of-time due to the game taking a different course (+/- x% combat effeciency in 1940), or simply feel arbitiary since they are mandatory (nerfing-events)? Seriously, good luck with that.
The fact remains: If both AIs are the same, playing both at the same strength, france should actually win. Germany won in 1940, because it made the right moves, and france made the wrong ones. It just boils down to that.
Since the fall of france may be pivotal to some games, the player(s) should have at least the option to have it occur. The way to do it, is to tell the french AI, in case of war with germany before a certain date, to have one army group in the maginot line defending, and another at the northern border preparing for an invasion of belgium, to be executed as soon as the germans invade it - and then have that army group run for quite specific targets, not changing its orders for a week or so, after the execution of the invasion has been triggered. All of this only, when a tick has been set in the game options (and accordingly for germany).
EDIT - BTW: If the AI will ONLY try to be smart, what will the chances of Barbarossa and Pearl Harbor occuring be? How likely will WW2 start at all? Should the german AI declare wars in a smart of in a historical sequence up to barbarossa? Should it be prepared for the war it chooses to fight in whatever way?