But then the 2004 DVD editions screw up the sabers BIG time, in both movies. Vader's saber is pink and orange. Luke's saber looks like it has a solid core sometimes (or it turns from white to yellow and back). The saber clash in front of the Emperor looks like crap now.
The bad colors and overly dark picture of the 2004 DVDs need fixing, for sure.
Other things to fix for ROTJ 2004:
Green matte boxes around ships throughout the space battle.
Fix the cardboard troopers in the "Emperor's arrival" if possible. Or at least make them look less like a matte painting.
Restore Han's line "It's allright... trust me" in barge fight
Either clean up the Sarlacc beak so it looks more natural, or remove it.
Remove the "Emperor's slugs"
Han Solo's reflection briefly in some blast glass right before the bunker blows.
Fix the part where Luke is kicking that guy on the sail barge and misses him by a mile yet the guy flies back anyway.
Nix "Jedi Rocks" in favor of Lapti-Nek.
Nix the flute montage in favor of "Yub Nub" or perhaps a subtle blending of the two (the ruckus Ewok celebration transitions into the "saga ending" of the worlds being freed and so forth, culminating in the return to the bonfire celebration).
Restore Shaw's eyebrows to the unmasking scene. If prequel continuity is a big issue, people might object to this. But even so, something needs to be done about that really fake looking bald cap wig and the fact that his face now looks far too gray in the 2004 edition (doesn't match ESB at all or the original version).
Restore Sebastian Shaw to the Jedi Spirits scene.
Remove the ring from the Death Star explosion.
Definately delete "wesa fwee!" from the ending.
ESB fixes:
Fix the continuity error created by the "new windows" (now you see them, now you don't) on Bespin between the time Lando is showing them the tour and they get detained by Vader's men.
Restore Fett's old voice.
Correct the asteroid that has an explosion in it right before the Falcon and TIE's reach it (for no apparent reason). If it's going to be a collision it shouldn't flame up like it's a laser hit or something.
Fix the problem where Luke's saber is still on as he leaves the cave (yet you hear a saber off sound).
Restore Luke's line "You're lucky you don't taste very good" in the swamp
Fix any instances of "black R2D2 panels" in space.
Fix the transparent cockpits in the snowspeeders (for good this time)
Remove the obvious "puppet stilts" in a few shots of the AT-AT's.
Fix the saber colors, making them more consistent with the other movies.