i feel like adding mountains would be very cool so that you could make maps more detailed and certain areas of the world/map would be harder to get to kinda like how in Europe Italy is protected by the alps, maybe you could make it so you cant get their on the Europe map. In a way i guess it would be more interesting and in certain places you can only get their by water. You could also make something like a mountain pass that makes the mountains able to be traversed by army's in that spot. I don't know if that sounds interesting or not but maybe you could do it in the next update so the game has a little more depth to it.
thank you if you actually see this (and possibly add it?) jokupelle or whatever your name is.