Currently, crowns gained and lost is too extreme at the high levels. I have posted about this before here. It leads to situations where the best course of action is to sit out one or more wars.
To counteract this, I suggest a 20 crown bonus to guilds that clear the map but lose the war. This would still allow a brand new guild to be in contention for the top spot within two months, and maybe even one. It would also prevent top guilds from resting on their laurels. In addition, it would give guilds that have lost a war something to strive for.