I'll give you a vote.
I would love to see smarter interaction with ai and buildings *and* I would like to see the "garrison buildings" waypoint as well. Even just making 'seek and destroy' clear buildings would be nice, though that could get a tad annoying if they try to clear entire towns in the wrong direction or something. You would need to be able to direct them to the buildings you wanted cleared.

You can garrison buildings in the editor with waypoints, am I missing something here? Just put the waypoint over the enterable building and you can have them man the positions that are available.

Not sure you can get them to go in without the waypoints (which I would love to see), but it's definitely possible using the editor.