None: When Luke releases the cable and falls from the AT-AT, the shot seems wider. (there's a button with a dot not scene before) and the blue button is now black.
https://picasaweb.google.com/102542760950977079734/EmpireSpecialEditionChangesHD#5673411116828834546
I disagree with this one (not the glue but the widening). The 2004 master generally has much less cropping than any other home video release. It is not a deliberate change, just a result of better video mastering technology.