France declaring war on Belgium and Holland so that it can out flank German forces is a bit un-realistic. Firstly, England was guaranteeing Belgium's sovereignty and would either have stopped the French attacking Belgium or withdrawn their troops from the war in protest. Secondly, the people of France being a Republic and all would have had civil unrest against the war with Belgium. Thirdly, Belgium is pro-entente and France declaring war on a possible ally would have had a huge negative impact on this. I don't mind the what-if of France doing this, it's just I don't think that France should be able to do this for free in the game. They should be taking a huge NM hit for doing something that drastic. I've played thru version .02 twice as The Central Powers, and each game France declares war on Belgium if The Central Powers don't. I don't declare on Belgium as CP's which delays the British entrance and it keeps the front smaller. If the CP's declare war first on Belgium, Britain automatically declares against the CP's, so why does it allow France to do the same with no consequence?
I agree with this logic; however, Joffre did advocate (even though he was overruled) before the war for such a plan in case Germany focused on Russia since the Franco-German border was heavily laden with fortresses and he knew Belgium was ideal for French forces to outflank the fortresses more quickly to invade Germany proper in order to aid Russia (see https://en.wikipedia.org/wiki/Plan_XVII). So, if Russia had been facing a large German army from the beginning, it's conceivable that after about 2-3 weeks, and assuming the British had declared war about this time out of sympathy for the Entente, that the French and British may have agreed to put military pressure on the Belgium king to either join them, allow Allied forces to traverse their territory, or possibly suffer invasion. It's debatable if the Belgians would've been any more amenable to these overtures than they were when Germany presented their ultimatum in our timeline, but maybe the game could have another possible outcome, besides a French DOW that makes Belgium a CP minor, which is Belgium activating as an allied minor, either fully mobilized, or with only detachments in Brussels and Antwerp so that Allied forces can march through unopposed. Perhaps even a DE could pop up two turns after Germany not declaring war asking if the French player wants to spend 100 MPPs over two turns to put military pressure on Belgium. This would then be added with any spending on diplomacy, but with a higher probability gained from the military effort, but no guarantee it will turn Belgium. Would add an interesting twist to uncharted territory.