The period of Napoleon total war (1796-1815) has a big problem : a lot of states changed several times the uniforms of their armies.
For the french: the revolutionnary uniforms are not the same that during Empire ( and I could speak also of the changes during 1804-1815).
Some countries changed also of uniforms like Prussia or Russia ...
Some nations like hessia, saxony have been ennemies or allied of Napoleon at differents periods, and they have different uniforms.
Some, like bavarians, kept their uniforms when they fought against Napoleon and when they were allied with him.
All of that is very complicated but if noone of CA has think about it it could create very strange things on the battlefield. I thought about it seing the trailer yesterday: they speak about the Italy campaign and we see empire french line infantry and not the revolutionnary one with bicorns.