Currently it's impossible to rebuild a lost wall turret without destroying/rebuilding adjacent wall segments.
Solution in this patch:
Destroyed turret is replaced with selectable object, that can be upgraded into previous structure wist some resource cost compensation.
This object does not block pathfinder and movement.When wall tower is destroyed, new entity (slot) is spawned at its position, which is invisible until placing wall.
If player chooses wall as building, slots where can be rebuild tower are displayed.
Placement is snapped to this slots and in this case player can rebuild tower.
To be able to build wall and another segments, It can be captured through territory decay and can be destroyed only by its ownertower has to be rebuild first.
These tower slots are destroyed when foundation is placed on them to avoid multiple tower buildings.
--------------------------------------Currently when there is some tower slot, any wall tower (even palisade tower) can be build on its place. (now you can rebuild wooden tower with stone tower and join or create mix of different wall types.
I am not sure if I covered all wall turrets and new object has all needed properties.