There are, naturally, a number of different points of view. One point of view is that the rear view camera is just an app (and this appears to be Tesla's take on it). Another view seems to be that it's just a UI change and everyone should just get over it. Some seem to think it should only ever be used when backing up.
My point of view is this: When I bought my first Tesla, being able to keep that rear view camera up all the time was a fantastic feature. The pick-up truck I drove before had a very large FOV out the rear view mirror, and the Model S didn't. The rear view camera more than made up for this loss of view, however, as the FOV on the camera when coupled with the side mirrors meant that I no longer had any blind spots. Any cars that were passing me (and this is the critical piece of information wrt my use case), I would still see the back end of the car in the rear camera view while the front of the car was visible in the side mirror. No blind spots.
But, for this to work, the rear camera view really needed to be close to the same level as the rear view cameras. The way the center console screen is mounted in the Model S, I can't really see the rear camera view when it's at the bottom if I'm holding onto the steering wheel with my right hand as my arm will block most of the view. Locking the view to the bottom of the display means I can no longer use it to check around me when changing lanes. I used the camera more for lane changes than for backing up by far. Is it completely useless to me? No. Has its function been significantly hindered? For my purposes, absolutely.
At this point I think Nissan and other car manufacturers have an edge on Tesla in this regard. At least when you back up in their cars, you get a full 360 degree view around the car. IMO Tesla has taken a step backwards in capability and, as far as my use case is concerned, safety.
You are of course welcome to use the capabilities Tesla allows you to keep whichever way you want. I'm currently trying to decide whether to mount my old Nexus 7 tablet on the dash and connect it to my dashcam to replace the capability, or whether I want to ask for a firmware downgrade.
(I might add that I'm underwhelmed by the lack of FSD features that had been tweeted about, puzzled by the inclusion of video games and indifferent about the rest of the UI changes on the whole)
