I got a used iMac and the previous owner deleted the Classic folder and now I can't install Unreal Tournament, or Quake III, or any of my old school games
Go for it! screw OS 9 dependency. delete the System Folder as well as Applications (OS 9)... after you make sure there's no X-compatable apps inside that you use (for instance, Appleworks itself runs in both). And congrats for cutting the Classic umbilical cord