Would it solve some of what you are wishing for if you were able to push and pull layers of a wall in plan similarly to how you can push and pull wall layers in section? For example you have a wall that is made up of gyp/stud/plywood/brick, at the end of that wall you could grab just the layer of brick and pull it beyond the end of the gyp/stud/plywood.
This could also be a solution to the wall join problem that in my mind has always been a pain, when you have many layers on a particular wall it doesn't always join how you want at the corners or intersections.
Or, what if you could somehow use the "split face" and "edit cut profile" tools in tandem edit a wall. Say for instance, in the example above, I wanted to cut away just the brick in one area, leaving the backup wall, to insert a book shelf. But to make things difficult, in plan one side of this cutout in the brick, the ends of the brick are rounded into the opening...
This would also allow you to have a long run of, say gyp/stud/gyp wall, that somewhere in the middle you have a cavity wall that springs off of this, well you wouldn't need to split the wall and create a new wall type, you can just trim off the gyp board inside the cavity.