There are two features I think would allow for more strategy:

- One-Way attacks: As the name suggests letting people choose one-way connections on custom maps, so if two zones are connected, you can only attack (and maybe transfer) from one of them to the other.

- Bombardements: Connections that allow you to attack, but not conquer a territory. It will always leave at least 1 enemy army on the territory. Could be combined with one-way connections for e.g. a zone on a hill, where you can attack several zones away from the hill not directly adjacent, but not conquer them.

if this was implemented, perhaps there would need to be some kind of indicator (like arrows) present on the maps to show which territories can/cannot go where, since if you had to go and check every single territory to see whether it had any of these settings on it, people would hate it i think :P