DontHateDefenestrate
Recruit
For example, make it so that place where there are horses will have more cavalry (or recruits with bonuses if you make them cav), and places where there are woods recruits that are better archers (or more likelihood of Highborns if it's a Battanian village for example). This could be a really fleshed out system, letting players strategize their acquisitions and building investments based on the kind of army they want to have.