Currently it's impossible to rebuild a lost wall turret without destroying/rebuilding adjacent wall segments.
Solution in this patch:
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, tower 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.