1. Would it be possible to give the M1A1 better range than other MBTs like in real life (at least at one point)?

2. Should the Ironclad be a unique upgrade for the Sloop? It fits a late Enlightenment Age to Industrial Age transition quite nicely.

3. How about Repeating Rifle Marines? They could be another Enlightenment-Industrial transition upgrade.

4. Gatling Guns as another Enlightenment-Industrial transition unit? You could take the Cannon model, swap the barrel for the Advanced Machine Gun's barrel, and take the sounds of the Machine Gun.