I would like to see temporary ones like encampments, etc that you can use to control mountain passes and similar without having to build a whole fief and removable after a while.
Already planned and could be developed/modified but here is the basis :
When an army doesnt move, it automatically starts building a camp.
After 24 hours of complete immobility, the camp is built. It will provide a little defense bonus and small food generation (represented by scavenging around the camp, it will also balance the food consumption of an inactive army).
After 3-7 days if the army still havent moved, the camp will upgrade into a fort. It will provide an average defense bonus and still the same small food generation (it will never become a good economical choice).
We could add a 3rd upgrade after a month of not moving but not planned atm.
All this knowing that you will have 2 kind of armies : "your" army (direct control) and "AI" army (semi-direct control). You will be able to field multiple armies (the total capacity will increase/decrease with game rules we have to decide on) so it will allow a lot of possible moves (like in chessboard games).
This would also help "AFK" not getting steam rolled if they forget to move their pawns or have a busy week-end.
Also distinguishing between wooden and stone bridges would be nice to allow for more variety (stronger but permanent or weaker and destructible to cover your retreat).
Didnt think of it but thats not a bad idea, since we already have 2 different paths (trails & roads).
About the movement difference between 1 person and 100000, it is mostly due to coordination issues, when you move, you need to replenish resources (especially water), take breaks for food, sleep, etc, which for small groups is not too hard, but for bigger ones can cause significant delays. As 1 person you can replace your horse and keep it fresh and fast for longer, for bigger groups this is harder.
If done right, food consumption will be the end all be all : if you have 100 000 guys you will consume 100 000 times more food (everyone eat approximately the same quantity of food, we wont go into different food quality...). then if you want to move 100 000 guys, they will not be all packed into one tiny hex, so you will need to have other armies accompanying you if you want to punch a crazy amount of men. But speed will not scale with size, only with where you go and with what troop (mounted or not mainly).
Then, we have to decide how we will manage a multi-army entity on the map but we should be able to find something.