Are we talking about the 4k file fox has, or the 4k copies being sold?
They have something that no one is getting the best version of. I know the difference between a raw video stream, and a lossy compressed one may not be visible to anyone that isn't a pixel peeper, if at all, but people out there buy things like this all the time for that last .1% or .01%.
Usually when you properly want to change a grading, you start with a lossless image, then encode to make it small. You don't change an already encoded image because the result is inferior.
I'm suggesting the most flawless copy of the film possible be made available. That'll be something terabytes in size, and not 100GB or less.
I want to add that I'm happy with DVD level picture quality if it is displayed at the correct frame rate, and the audio is at least as good as what standard blu ray offers. If the language I'm using is still not clear, I'll clarify my first statement.