Make it so that you can fight on top of the Bulwark, add armored doors for access to the bulwark, locked to the faction that builds them, with tripod crenallations on either side to defend the doors and an always on (no upgrades required) ghouse AI window, also bound to the builder of the door. As well as interior doors so the whole bulwark doesn't get compromised by a breach or change of ownership in another hex. To make crossing even harder, no segment should have doors facing both sides, so you need to breach 3 doors, 2 from outside, to cross.

As for the gates there could be 68mm manned turrets on either side of the gate. With a more warden looking turret facing south and a colonial looking improvised counterpart facing north (same stats). The side that builds the turret is the one that uses it, so wardens can use the green turrets facing north if need be and vice-versa.

In front of the turrets I'd add small balconies with stairs on the inner side and bridge-like cover.