I was just watching ROTJ again and one thing i noticed is that a whole section of the movie looks almost out of focus. Anyone who has the blu-ray rips just check the part where the Tydirium is approaching Endor. It lasts until around the speeder bike chase. It's the same on the HDTV 2004 version too. It is such a huge drop in image clarity it looks almost DVD upscaled. Compare it to the rest of the movie and you will see what i mean.

EDIT you can check out just how different it is here: