Well I didn't expect my army of 1750 to take the castle of over 8000 strong. Just meant to chip away at it (although using superior tactics to methodically take spawn points and win the castle is always the goal, no matter how out numbered).
And I highly doubt it would happen, but it would be nice if damage done to castles with catapults carried over to the next battle unless they paid for repairs. So that way you could actually have pro-longed sieges, and are building up to something. Also, if you take over a castle after completely destroying it, the castle is still left in shambles. You either repair it with money, or over time with manual labor (like instead of working/recruiting/doing nothing, you add the option to work on improving the fief).
I think that would make sense, that if I destroy half the walls on the castle, and someone attacks me the next day after I take it over, the walls should still be down unless I spent a shit ton of money to repair it in one day.