I find that in some larger buildings the design is to have a large open area that has smaller walled-in rooms in the middle of the rooms. (Specifically office buildings).
What I am asking for is an option to "Cut a Hole" from Floor to Ceiling and replace the opening with walls in the middle of the room.
The process I use now is to divide the room into multiple sections and then open up the "walls" that are the openings. This unfortunately does not let you place calc points in the room sections as one large calculation, unless you do a 2 or 3 point calc plane, this requires more work to clear the unwanted extraneous calcs.
This tool would save a great deal of time in these situations. Simply trace the outline of the rooms in the middle and take it away!