Oh I really like that. I posted a similar suggestion recently with more details here. In addition to ramparts, walls should have merlons, etc, and enemies should use ladders to climb up and fight on the ramparts instead of destroying walls (which in reality would require sappers or trebuchets and a lot of time).
Another idea I like by the OP is tournaments. Also adding raising horses, for use by tourneys, cavalry units, and racing (or even hunters for far away game).