NeverarGreat said:

Another test to see whether the original sky color in this shot could be recovered:

I'd say so. But unfortunately for the DVD, most of the detail on 3PO's shoulders is on the blue channel, so it's a compromise.

JEDIT: I've updated the image. This one keeps almost all the blue detail by turning it red.

The problem with this shot is that it wasn't just recolor-timed, the characters were cut out of the background and the background was swapped, so you can't "pull out" the original colors, because they're just not there.

Also, I was horrified by how bad v2.1 looked in your comparison, so I checked and this is what the actual v2.1 frame looks like:

As you can see, not only are there some really ugly compression artifacts in your comparison, but the colors and brightness are wrong as well.