Haha, it's clearly beyond my ability to explain this to you. You're just going to have to try it and learn.
But I'll give it one last try:
One can only hope that you're either exceptional enough to succeed or that when you fail you understand that it wasn't because "suburbanites ruined a perfect plan because they can't imagine a blah blah blah" and learn that you're constraint solving in a democracy where other people have voices and your perfect solution needs to have graceful degradation as it makes allowances for their opinions so that it can get sufficient support to pass.
If all you do is create additional liability with grandfathering in of existing designs, all you do is lead to propagation of current designs.
But I'll give it one last try:
One can only hope that you're either exceptional enough to succeed or that when you fail you understand that it wasn't because "suburbanites ruined a perfect plan because they can't imagine a blah blah blah" and learn that you're constraint solving in a democracy where other people have voices and your perfect solution needs to have graceful degradation as it makes allowances for their opinions so that it can get sufficient support to pass.
If all you do is create additional liability with grandfathering in of existing designs, all you do is lead to propagation of current designs.