There is a problem with making France to powerful. That is that the game will no longer be very playable in MP. I think it is jju_57(???) that said this.
I play in large groups with 12+ players. France and Britain each have a player and sometimes even Poland does. If it is possible for Poland and France to win WW2, well, lets think about all the paying players that have invested hours of their time in this game that are playing Russia, the USA, Japan, Italy, Hungary, Canada,.... you get the idea?!?!
If a good/decent British player and a good/decent French player can stop an excellent German player even 35% of the time... We will have issues. Who wants to surrender before they get to use their brand new shiny Bismark battleship?
Although I think France should have a chance, it should be slim. It should have a good chance at hurting Germany which would give it purpose. But outright defeating it would be nearly game breaking for me. Historical or not.
By the way, I hardly ever play SP anymore. The AI is sooooo bad. Even a revamped AI will end up being fodder for many of the people I play with, so we must have our MP!!!
The answer --> Keep the AI easier. It will satisfy the masses and allow someone to play France and still beat Germany. However, the forces should still be stacked against France. Elsewise... no fun MP game.
I sympathise with this view, but what you're saying is to move away from history to provide MP balance. If the aim is a balanced MP game with a WW2 flavour, rather than a WW2 game that's as historical as possible but the mechanics are still fun, then we're taking a whole 'nother approach to game design than HoI has traditionally.