I think Xion's is the most consistent and is apparently almost as good as the Spec Ed DVDs!! (How on Earth has he managed that?!)
I suppose someone might concentrate on inserting the altered scenes back into the Spec Editions. There would be a quality jump when you went back to the Laserdiscs but if Xion can capture so well then you might not notice that much! Plus it would be easier to concentrate on one scene (Hans Shoots First for example) and get that perfect rather than trying to do the whole film in one go.