Okay this might be a long post but bear with me. ( all of these suggestions should not be forced into the first release unless you want to)
Firstly,I think sharpshooters should have the unique option of climbing up into trees. Maybe just have an option where if you are playing as a member of a sharpshooter regiment, if you stand in front of a tree and press T or something you get on a tree.
Also, you have mentioned that you want to have VOIP in the game. If you want to make the game realistic you should make it so if you yell loud enough the other team's players will be able to hear you. This would give people a reason to not yell at the top of their lungs " Chaaaaaaarge" because the enemy would here you and kill most of the chargers. If you add ambient noises like birds cawing or the wind then maybe people will make signals. Just imagine, Sharpshooters hiding in the forest. A Yankee regiment walks up the road and doesn't see the sharpshooters. The leader of said sharpshooters goes "Caw Cawk , Caw Cawk" and every one springs up and starts shooting. I dare you to say that would't be fun.
Finally, a question. Will going prone be a thing. If it is going to be, then the reload time should be around 45 seconds instead of the regular 20 so people don't abuse it.
P.S. I am very hyped