Implement an American faction. (PROPS TO NA)
USA did nothing in Napoleonic Wars (like in WW1), they just got rekt in the War of 1812. If you want to add new nation to the game, Rheinbund and Duchy of Warsaw are good choices, because these countries actually did something in this time period. Personally, I would like to see Kingdom of Naples, but their army was... well, not the best (even the Spanish one was better), but cool uniforms tho.