Impassible trenches

[StormProxy]

Add the ability to make deep trenches that fill with water. or a very deep hole to stop raiders passing through a section of base.

[NinjaDiscoJew]

Maybe with this, the raiders have an ability to make a bridge of sorts, but it takes them quite a while to make it. That way you can't just build trenches around your base and be untouchable.

[StormProxy]

exactly. make it like a siege kinda like in stronghold you get to build equipment to attack another base like siege towers and ladders or fill in the motes they made