Build whatever you want becomes the most profitable houses to build/sell. Monster homes where single family homes were. Seedy businesses beside schools.
You probably want to have some planning.
You probably want to have some planning.
But in any case this is all solved by Tokyo minimum nuisance zoning. In short, what that means is you can't build your seedy business in your school zone but you can put your school in your seedy business zone. The zones don't directly prescribe how land can be used, only limits the amount of tolerable disturbance allowed per neighborhood. Things get built where they otherwise wouldn't, but no one has to deal with more annoyance than they bought into.