I'd like to see more maps designed like [this one](http://warlight.net/SinglePlayer.aspx?PreviewMap=7578
To have mounatains, forests, lakes/rivers, bridges/mountain passes, etc. as boundaries makes the maps more realistic.
For instance, in the modern age Savoy controlled the mountain passes between France and Italy. This made Savoy a strategic state: control Savoy or have Savoy as an ally or client state and your access to Italy and ability to threaten France is ensured. Another example: Louis XIV's expansionist reunion policy (ie, feudal legal claims to German cities used as a casus belli) were in part made bc those cities were ports into the Holy Roman Empire (and, vice versa, entry points from the HRE into France!).
Geography influences war. More geographic boundaries in future maps would be nice.