It shouldn't be that difficult to make them replaceable. Video games have featured terrain customization for, what, 20 years? 30? It's silly how limited the design functionality is in this game. When I first started I was laying roads and decorations and everything until I found the roads could only go on a specific grid, and there was no area select tool to move things around. Now I just have a few limited aesthetic touches but mostly arrange things by practical considerations like putting most of the buildings with the same task time next to each other, and having almost no roads so I don't have to hunt for characters.