Many of these ideas have been posted before, but I'll repeat them just for good measure:
-Smoothen the Tauntaun movements
-When the Wampa grabs the Tauntaun, the arm is seen just a few frames too long. You can easily tell it's someone wearing a glove. A few frames cut could do the trick.
-Chewie's roars are at times annoyingly loud, especially on the 2004 DVD version. Most of them could be toned down aout 5-10%. I double checked on linear studio speakers ;)
-At about 7 minutes into the movie, in the rebel base, there's a shot in which a Tauntaun is in the front of the picture at the beginning of the shot. It's kind of a cliché 80s shot to liven up the picture, but since the TT looks fake and out o focus, I think it doesn't really add to the scene.
-In the Wampa cave when Luke frees himself and falls to the ground, the Wampa should be closing in, but he is nowhere to be seen. That should be fixed. Aside of that, I can live without the 2004 shot of him. If you're keeping the original version, maybe you will want to add a bit of a camera shake, when he closes in on Luke.
-Everyone talks about the Hoth shield, but we never actually see it. Depending on what you want to do with RotJ, you may want to add a shield opening, when the rebel transports leave Hoth.
-Hoth Battle: Now the dream would be to see a much bigger battle with added AT-ATs and AT-STs, but that would probably be way too much work. Adding a few background AT-ATs as in your trailer is cool though. I did notice, when I watched the movie, that the battle seemed pretty balanced. There were neither too many Snowspeeders nor Imperial units. This balance should be kept. One scene where I could imagine the AT-STs would be when the rebel soldiers are fleeing and you see them running towards the Camera with the walkers in the background. You could have some AT-STs behind them picking them off as they run. [img]http://images.wikia.com/starwars/images/6/67/Battle_of_Hoth.jpg[/img]
In the story, the AT-STs attack Ion cannon. Could be fun to see it get blown up, but could possibly just distract from the main story.
-Upgrade laser impacts on AT-ATs. Some leave no mark at all (even the shots from the big stationary turrets). Maybe burn marks on the AT ATs would look interesting.
-Add whirling snow when AT-AT falls. Something that heavy should create quite an impact, even in wet snow.
-Inside the rebel base, one of the Snow troopers is weirdly holding on to his mask. Looks wrong. More Snow troopers would be cool, but I have no idea how it could be pulled off.
-Black R2D2 -> Blue
-Maybe more TIEs could be added to the asteroid field chase. As it is, I find it hard to imagine they'd only have 4 ships available to chase the Falcon.
-Add a cam shake to the interior shot of the Star Destroyed during the "evasive action" scene. As it is, you just see actors falling around without getting a feeling for the forces at work.
-There's a really obvious real-life snake early on in Dagobar (Boa or Python). Could be recoloured. Same goes for the Iguana in the cave. Not sure he is necessary at all.
-Upgrade explosion of Star Destroyer bridge hit by Asteroid.
-Entering Bespin: Not sure if this was upgraded in the 2004 versions, but the clouds in the back of Luke's X-Wing looked really bad in the original.
-Just before the Duel between Luke and Vader a door closes before R2. Just not completely.
-During the escape scene, a stormtrooper is hit by laser fire without visible impact and just falls down. Upgraded impacts or burn marks on stormtroopers would be an improvement
SE Changes:
-The new exterior shots of Bespin look nice. The "upgraded" interior shots however don't work. The suspense suffers from opening the place up and the orange lighting distracts from the white interiors. It also takes away the claustrophobic feel of the original.
-New Emperor scene: A hybrid between 2004 and RotJ sounds best to me. Don't like the new dialogue though.
-Finally: The infamous "Bring my shuttle" Scene. The SE Version is just horrible and disrupts the flow of the rescue scene. However the same could be said about the old version, which also notably cuts into the music. I consider it the only major flaw in the original movie. I'm not sure the scene could be placed any earlier, probably the only thing to do is keep the original version.
What probably not to do:
-Adding lightsaber retraction shots to Luke leaving Wampa cave and getting blown out of Bespin window scenes. It would just distract from whats going on and in the latter scene there's a lot of noise anyways.
-Adding any music. It can really change the feel of a scene and to be honest, I think the added music to the OBI-Wan and Vader duel is the only thing that really didn't work in your ANH edit. Maybe it'd work differently for ESB since the unused music was originally written for those scenes, but the scenes are pretty much perfect the way they are.
Hope this will be of some help for your edit. Once again, thanks for the tremendous effort. ANH Revistited really put the official Special Editions to shame.