I think it would be very beneficial to be able to upgrade wall segments to corner posts, with of course a greater total resource cost (with wall segment cost plus the upgrade cost) than just building a corner post in the first place.
I think it would make things alot more athsetic with altering and adding walled in areas..
Also it would solve the issue mentioned before, and that my friend has, of not being able to place a gate due to miscounting the wall segments before the gap, and not having anywhere near enough humour to make a dent in a stone wall (without going down the route of making it easier to destroy your own walls and opening up villages to risks of spies being handed the power to easily let in raiders).
Thoughts?