I agree 100% with dvdmike. What is being proposed here is a fan-edit. The colours are exactly as was intended by the filmmakers and therefore no "fix" is required.
My personal view: While MOS may not be perfect, I have absolutely no problem with a different take on the character complete with a darker, less colourful look. We already have the bright and brilliant Christopher Reeve Superman movies to enjoy and I'd much rather see a new movie attempt something different with the character rather than just rehash the same look and feel all over again. For all MOS's flaws, I'd really rather encourage this sort of thing than whine and complain that it doesn't look like my idea of Superman.

So good luck to all who are interested in this fan-edit but it's not for me and it really doesn't belong in the preservation section of the forum.