I would love to see it load various zoning laws and as well as building requirements for a particular city and then work within those constraints.  There is not a lot of regular sized conforming building lots in bigger cities.  In many cases, you have to get a variance from the zoning board before you can even get a building permit.<p>What might be a cool feature also is a renovation tool that can sort of plan what you see on a show like Property Brothers.  Given a blue print of the existing house, the tool can help you visually plan a renovation.