Lo-Fi Games

I've notice characters must be on ground level in order to build something.
I'd like to suggest to be able to build while on walls. I've found walls are somewhat difficult to build in hilly terrain.
Being able to build walls while being on top of an already built wall would be great then I'd be able to build my mountain fortress!
I already have a spot in mind and have my city there working away but I find myself attacked without great defenses.

Also if I could build small gates at the very tippy top of my ramp that leads to my wall that would be cool, so my gunners are protected somewhat but I'd just be happy with being able to build walls... :\

I've also found it hard to block off key choke points around elevated ground where a character can come up to a plateau, I would try to build a wall to cut off this choke point but instead I have to build a wall around the whole entire choke point rather then straight through.

put ramp on wall
send your person to the very edge of the wall walkway next to the next wall part you want to build.
select build. if you are close enough to the edge of the finished wall, you can indeed build your wall that way.
i used this method to build mine that were on hills. but sometimes your character gets stuck. rebuild navmesh. then save game and reload from in game, thi usually free's them.