It has come to my attention that my hotfix isn't getting noticed on TW, so I'm being a little more aggressive.Repository link
The fix is simple - I modified all the town siege scenes - the bugged ones where the AI couldn't jump over the walls.
Installation is simple, drag and drop in the M&B\Modules\appropriate mod\scenes\ folder, and let it overwrite. It'll overwrite scn_town_x_walls.sco files 1-14, and nothing else.
The fix works for all versions of M&B where the .903 type town siege walls are used.
TW thread: http://forums.taleworlds.net/index.php/topic,32083.0.html
Feel free to add it to any and all mods, just remember me in the credits.