I don't know if this has been mentioned before, but the forthcoming centenary of WW1 prompted me to suggest it. I'm thinking of the period March 1918 to the end of the war because this is when both sides were at the top of their game, tactically speaking, and some movement had been restored to the Western Front. It would also make it possible to introduce the US Army into the game. I imagine the game engine could cope with it; by this stage of the war, infantry tactics at the small unit level were not too different from those employed in WW2. Some changes would be necessary of course; no radios, more elaborate entrenchments and a greater focus on pre-planned artillery bombardments.
Is there any interest in a game of this sort?