A list of things I think would make people actually get this 'Mod'.
-New animations (Not to many, but just so people see they are ''new''
-New sounds (The sounds now are like you shoot a cannon with every musket shot)
-New maps (The maps are getting extremely boring, lol)
-A new redicule (Try to design something fitting to the time, I know it's hard but I've seen it before) -
Spoiler
Or remove it so I will never be pointblanked again! Muahaha :p Just kidding
-New regiments, also. You might not have to add the Netherlands, you could add Dutch troops to Britain? Just a suggestion though.
-New factions (The Netherlands, Poland (Duchy Of Warschau or something that is, sorry if I am incorrect), Spain, and maybe Sweden)
-Remove certain things. (Maybe remove Russian partizan with derp weapons, and only add Russian Militia with actual muskets.)
-Add some things for the sapper maybe.
-New textures, make some things look older then they are now, even by then they probably didn't look so shiny, and I dislike quite some textures, such as the sandbags, and the cannons should get a new colour!)
-Maybe, if that is possible, make is so that rain doesn't go through buildings, would be awesome!
-Misfires, if a map rains or something, that a musket has misfires.
These are just suggestions, some are better some are not even necessary. I hope this helps.