Hmmmm....I didn't think about that problem.
Fort Pickens I don't believe was in ACW (only ACW2, and its a fort).
Though Dry Tortugas is a problem. And there could more similar style islands when I'm done (not sure yet). Though amphibious assaults were very rare in the American Civil War (want to stress, very rare, most landings took place at least a few miles away from direct hostile owned territory).
Dry Tortugas probably will revert to a regular fortress in ACW2, since the Norfolk problem has been solved due to the new map. Most of the Confederate coastal cities are "inland". Chincoteague is staying though to assist the AI Union. While it is unrealistic for ships to go back to home port after being damaged, I don't see how this can really be modified realistically. I think the much faster naval movement will alleviate this problem some.
I guess the main reason why I suggested amphibious infantry for late 1864/early 1865 tech is because there were some coastal landings made by the Union during this time (Mobile and Wilmington are examples).
Rocoteh, did the US Marines exist during the American Civil War? If so we could set up a basic Marine type unit, and then let amphibious infantry be the upgrade.
Alternatively, we could make infantry divisions amphibious (large size formations, more likely to be able to force an assault).
With regard to Cavalry being 4 movement, I'm not sure it would be balanced. Your typical Cavalry, while faster in movement than regular Infantry, still had to rest their horses frequently (every couple hours), and horses also had to stop to eat frequently (Cavalry usually foraged off the land). I would be interested in hearing more feedback regarding this issue.
Kentucky currently has Columbus, Bowling Green, London, and Pikeville for the Confederacy, and Louisville, Owensboro, Paducah, Lexington, Covington/Newport, Ashland, Maysville, and Frankfort for the Union. Most of these were significant to the American Civil War, with Covington/Newport being of good size for the time period (combined over 30,000 population). Maysville was an important Ohio River crossing.
Rocoteh, what is your opinion regarding the defensive bombard/offensive bombard on Divisional units?