I really hope they implement the CKII system of warscore gradually increasing if you control the territory that is being disputed. Maybe each province could have a "Willingness to surrender" value which goes up the longer it is occupied. It still costs the same warscore and gives the same warscore, but the AI becomes more likely to surrender it.
It would be good if that sort of thing scaled - so it would be much harder to get the AI to give up a core territory close to its capital, but easier to convince it to surrender a border province.
That way we can avoid the EUIII AI's tendency to not give up 1 province until 10 are occupied. :wacko: