Aww, come on… how can an engine be so ahead in some areas and so crappy in others. So, if all the code is there and it only takes a few modifications to work without the editor, then why doesn’t Epic make it happen?
I badly need to modify heights, make/fill holes and modify material weights at runtime 
I came to UE4 from Unity because I thought it would be better for procedural runtime-generated and runtime-modified levels and stuff. I guess I thought so mainly because of the dynamically updating NavMesh. But if you can’t even change the terrain…