Had some free time to kill, so I fixed it.
Mega Link (https://mega.co.nz/#!hgIiBThI!Et39h5Nnr9VyIhTPar-CSvR-WyD5UZBfYvu2O8gkH3o)
-Added a way for defenders to retake the gatehouse, simply a set of stairs to the right side battlements (one way trip, as newly spawned attackers climbing the siege tower will trap defenders in the gatehouse)
-Added (using existing, useless props) a blockade to stop players running up against the map edge near the flag
-Added some barrier_box to the stairs leading to the gatehouse (imparting collision to some of the beams at player level)
-Added some barriers to the primary route to flag (to prevent players getting stuck between the props and the wall in two places)
-Modified some barrels on the primary route to flag (clipping with ground, the wall, each other)
-Modified a barrier near the defenders spawn to provide better coverage
-Modified some marrows
-Moved the jousting rail to be more central to the colored dirt
-Moved an entire row of houses further into the ground to cover up some ugly stairs
-Moved some defenders entry points around (mainly out of areas where they can't spawn anyway, as they are outside the map border (if this has buggered spawns, I'll repair it))
-Moved a broom
-Minor terrain editing
-Removed two light_night props around the burning siegetower (if it looks bad at night, I'll add them back)
-Removed light_night and torch_night props from areas players can't see/go
-Removed some misc props in places players never go
-Rotated a building near the passage to hide some ugly roof clipping
-Rotated some barrels so they aren't all facing the same direction
-Scaled the sally doors uniformly to fit the passage