Why not just drop the "Early" in the series title. Rename it to "War in the Americas". It would broaden the scope and allow for more ideas.
PS: I agree Dion, The Seminole Wars would be an great topic for this series.
Future of Series?
Re: Future of Series?
I think they should combine Civil War Battles and Early American Wars, and include The Seminole Wars and a Age of Sails type game. After all there isn't much difference in the warcraft of that time period, only in science, medicine, and basic technology. This would also broaden the scope and allow for more ideas.
Re: Future of Series?
What about some naval conflict in existing games (patches).