Also, giving campaigns a purpose might be a step towards having wars with a goal, instead of "let's kill you".
Maybe, in order to do this, have campaigns have stated objectives? The general that creates it has to name a county/duchy/realm to attack, and receives bonuses to attacking those locations. County-specific objectives would have very large bonuses and realm-specific objectives would have much smaller ones. Defensive campaigns could do the same thing. In order to balance this you'd obviously need to make campaign objectives public.
In order to prevent people from just switching the objective of a campaign, maybe make it so that a general has to close a campaign, wait some period of time, and form a new campaign at his capital in order for objectives to switch?
