The Bronze Wall is less resilient and costs less to upgrade than the Greek, Egyptian, and Chinese upgrade to the Stone Wall, the Heroic Age Fortified Wall. It is therefore more natural to compare the Fortified Wall to the final Heroic Age Atlantean wall, the Iron Wall.
Bronze Walls can be upgraded to Iron Walls in the Heroic Age. The upgrade costs 600 food and 450 gold. The research time is 50 seconds. Iron Walls have 500 hit points and 2 Line of Sight more than Bronze Walls.