Back screen is already set to work as a "track pad" for the right hand side to dictate focusing point when the camera is at my eye. Once face is to the view finder, index finger is on the shutter trigger button, right thumb is virtually impossible to extend and reach/hover around the back screen to dictate focusing point.
Impossible to access mode dial with index finger and thumb (and even if you succeed, you would inadvertently press the back focusing button, reverting you out of mode editing function)
