The problem is how Lucas' ego has inflated over the years, to the point where everything he does with SW is an attempt to re-capture past glory of the days of the original film's release - not the film itself, but his feelings of those days. He wants it to be a "new experience" every time it comes out, no matter how many times people have seen it before. Restoring the OOT won't be a "new experience", it will be "recreating an old experience".
Keeping the OOT looking as shit as possible makes the SEs look better by default rather than any changes that might truly improve the films.