I don’t spend a lot of time keeping up with the space, but I could have sworn I’ve seen a demo that allowed you to iterate in the way you’re suggesting. Maybe someone else can link it.
It's not exactly like GP described (e.g. move bike to the left) but there is a more advanced SD technique called inpainting [0] that allows you to manually recompose parts of the image, e.g. to fix bad eyes and hands.
