This is a REALLY good idea! I think it would work best if it was very simple to use, too. For example, the Planning Tool that is used in the Prison Architect game would be perfect! You can click and drag to draw squares, rectangles, etc. to plan buildings or similar “square shaped” things (ex: parking lots). There is also a tool that lets you click once to add a single square (viewable in planning mode) block to represent “items” (for example, in that game, to represent where you will add a toilet, bed, or shower head).