I don' t think the case for the 7 is up to spec. If the 7 is 1mm thinner, it would be a lot " floppier". I really don' t hope so. Because this would imply that the 7 will still have these big chins and bezel if the 7 keeps the same 4.7 inch screen size .
There is an outside option/long shot though.
We have seen some vague pictures of a suggested iPhone without a physical homebutton.
If Apple decided to increase asp/margins/revenue by pushing an upgrade cycle to even bigger, more expensive iPhones (say 7+ and 7 pro), they could:
1. Release a 4.7 inch iPhone 7 , that is thinner, an enhanced design, and a better display, camera and soc. But with the physical touchid homebutton.
2. Release a 5.2 inch iPhone 7+ with an upgraded display with smaller bezel, upgraded soc, but with the touchid and homebutton integrated in screen by 3D Touch. In almost the same physical size as the 4.7 inch iPhone (perhaps a little wider) at the same price as the current 6s+.
3. Release a 5.7/5.8 inch iPhone 7 pro, with dual cams, even higher res display, smaller bezels, touchid and homebutton in-screen, and a higher clocked or Ax type soc with more internal memory, split screen multitasking capability , in the same physical size as the current 6/s+.