Not bad at all... Nikon finally found out the cause and solutions to the D750 issues, and will be providing the fix in a couple of weeks time.
My initial observation about the focusing sensor position was correct. All thanks to one of the poster on Dpreview that posted his picture of the interior of the D750 chamber. If I am not mistaken it was Brunobarolo who reposted here.
The next thing is the dark band, I don\'t think I see any solution for that yet, unless they add in a slopy deflector in front of the focusing sensor closed to the lens mount. This slopy deflector can be tape on just like the felt tape.