I think CA has plenty of 19th century conflicts in which they could perhaps take logistics and naval support to the next level. How about gunboats(ironclads) attacking coastal forts. Sailing up navagable rivers to shell a city and then land some marines . How about Engineers. How about railroads. Blowing up bridges and then being able to rebuild them would be really cool. Cavalry could raid behind lines and tear up railroads, raid depots. I think WWI would be a far reach yet, and I'd also like to see them go back to Rome, but the Napoleonic Age is just the beginning for nations having Command Staffs, War Colleges, an army corps system and large massed batteries. I drool about the possibilities.