As for the "one path" argument, making the button take you directly to the home screen doesn't reduce the number of paths. You exit the app via the home button and it takes you to one place. That's one path. Whether the path is to the home screen or back to the state you were in is a design choice that has no effect on the number of paths.
Personally, I think Apple made the right choice. It would be pretty obnoxious to be on screen 3, launch the wrong app on accident, and then be dumped back to screen 1 when exiting. I'd much rather be able to hit the home button and then immediately launch the app I intended to launch.