Here's an idea: Not all the armies at the start of the war (or indeed throughout) would have equal capabilities, due to armament, training, culture etc. Why don't we have the vanilla stats for each of the nations made unique to represent the capabilities of their armed forces, unit to unit? For example, the New Zealand infantry were widely known as the best on the Western Front, and probably the best troops in the entire war. Why don't they have stats to reflect this? Of course, they, like Australian and Canadian troops, were high quality, but extremely costly in terms of reinforcing and payment costs. On the other hand, due to the incompetence of the staff, Austrian troops were quite possibly potatoes in blue serge uniforms. Serbian regular troops should be excellent due to them being veterans of the Balkan Wars, but be hideously expensive and recruitment limited. Russian regular troops should also be inadequate like the Austrians, due to their humiliation against Japan, but be bolstered by a selection of elite units such as the Sumskoi Hussars. German regulars should be very good due to the quality of their junior officers, whilst France should not be far behind them. British regulars should be excellent, but like the Serbs, prohibitively expensive and recruitment limited due to the small professional army that existed at the time. The elite Ottoman troops should be known as the Young Turks, who were troops allied to Mustafa Kemal and his organisation and who fought harder and better than any other Ottoman formations. Of course, once one gets to conscription, the differences between nations should become less pronounced, but I want the campaign to make it so that I feel like I have to recruit conscripts, rather than regular infantry. I almost never recruit conscripts, and almost never have the need to.
Also, the French economy needs to be toned down a little. Hard to program perhaps, since the mod is based off a game set when France was overpowered, but if at all possible just toned down a little. I played a campaign as France where I only liberated (except for Alsace-Lorraine) and can field five full-stack armies in mid 1916 with no conscripts and making over 10k a turn.