A very nice mesh, but far from practical.
You have the crenellations facing a side instead of having them on both sides, for this to work properly you would need 4 walls which I think is a waste of space (to cover all 4 sides North/West/East/South). There are more reasons of why this wouldn't really be ideal especially for faster type or more realistic gameplay.
A good example would be this:
http://www.hiveworkshop.com/forums/models-530/stone-wall-158796/?prev=search%3Dstone%2520wall%26d%3Dlist%26r%3D20%26u%3DKitabatake
It might be a bit more complicated to fix now as you strictly added the way they must be facing instead of it being balanced.
For them to work in their initial form you would require:
-Heavy triggers to make them rotatable, not to forget that in game it would take more time so you have to rotate them in the correct order or if you're just playing to win you would just place them at random and have an awkward appearance.
-Otherwise you would have to make 4 models (left/right/down/up) instead of 2 which is a bother not only for you but for the creator as that means more weight and also you need 4 buttons free in the "Build" ability, in this scenario players would often just choose the horizontal or vertical not caring for the right or left.
This may seem like OCD but every little detail helps on creating a map and cutting corners will not do you much good, plus it would also help with the usefulness and practicality.
All in all I haven't tested it in game yet.