As long as the original versions were preserved as well:
-Re-rotoscope all of the blaster bolts
-Fix shots of Luke igniting and de-igniting his lightsabre to remove the jump cuts and so the blade 'grows' and 'shrinks' like it should
-Remove all garbage mattes (there are still some visible ones in the BDs)
-Restore the Anchorhead scenes to ANH
-Restore the scene of Vader telepathically contacting Luke while he builds his lightsabre to ROTJ