A real game-changer for creating buildings faster, in my opinion, would be the ability to drag a rectangular or square space, just like you can drag a rectangular calculation area from a single point, instead of clicking on each corner of the rectangular or square space.

This would significantly increase speed.

You would click much less and have the great advantage that the corners are always at 90 degrees. Most buildings still consist of rectangular spaces, making this an even more relevant improvement.