Oddly enough, I was logging in to start a thread about this exact thing.
Watching A New Hope, I was incredibly disappointed with the jump around in quality. And I completely agree.
I do NOT want any of the live action stuff refilmed (with the limited possibility of the initial 3P0, R2 scenes on Tatooine. The horrible color inaccuracies don't appear to be fixable.
But seriously, why not give us a version of the OT that looks totally modern. Bits and pieces of it already do, but parts of the film could be completely redone. By attempting to preserve some of the original special effects, Lucas is continuing to cheat himself of what he really wants: An OT that matches the PT.
Strangely enough, this alone is why the OUT is not being considered for release in any decent quality: Because George does not feel that enough has been changed to warrant viewing both versions of the film.
But imagine that that shot at the beginning of the Tantive 5 (That sticks out as a total eyesore versus the very much cleaned up Star Destroyer) was replaced with a RotS quality cgi version. That there are Tie Fighters added to the scene to make the battle bigger and more important. Imagine that some of the most dated ship interiors were replaced with a digital bluescreen, then replaced with the beautiful CG interiors we've gotten in the PT... I mean, look at that ugly brown door on the Tantive.
Now replace the droids in the JAWA transport with decent looking ones (get rid of the walking trash can, etc.) Repopulate the Cantina with new cgi creatures.
Anything that is not a physical main actor should be fair game to change up...
If Lucas sat down down, and put the OT in Post Production in the same way you would an unreleased film, and fixed it with modern effects the way you would a modern film, we would have something absolutely beautiful and amazing, complete with the performances that we all love.
And... with a totally altered film to show off, with a very very visible difference from the original... I think Lucas would release the OUT.