The cleanup I definitely agree on...I remember that orange shadow underneath Luke's landspeeder when entering Mos Eisley...that could go
Other things like cleaning the negatives, making the Death Star explosions more...explosion-y...yes, makes sense. I think the changes that don't work are the ones that have that 'tried too hard' feeling....they are there, but don't really add to the story. They almost make you look away from the focal point of the action. Some of the worst changes I think were the changes in the dialogue. ROTJ at the Sarlaac Pit when Han Solo is blasting a tentacle, he says, "It's alright, I can see a lot better." (which seems terribly rushed for the cut that the made). In the original, he says "It's alright. Trust me." On more than one occasion I found that Lucas needed to 'explain' to the audience something rather than let the audience figure it out. We needed to
explain to the audience that Han could see better...not just let Han Solo be Han Solo and shoot.
Bit off topic, but just another reason why I am eager to buy the originals.