I am struggling a little to follow your logic there John, if in reality all physical things and all space are expanding, we are not the center of the universe, and there is no big bang, but we still need a mechanism to describe how the redshift seen at any point is diferent to different observers. This looks like the essence of relativity to me. The terminology of an optical effect might be problematic, since Doppler shift affects all periodic sequential signals and all data, not just optical. To us, the hearbeat of someone in a red-shifted zone would appear to be 50% or so slower than our own. Is there something subtle I am missing?