Besides the obvious stuff (AT-ATs, Wampas, Fett's voice) here are a few I found:
* When 3PO gets turned off, he remains in the background of the scene, with Anthony Daniels still breathing. Since that whole shot is static, Ady could easily keep one frame of 3PO in the background so he is still until the ship rocks at the end of the scene.
* There are several space shots where you can see stars through the Executor, Luke's X-wing, and even Dagobah!
* When our heroes arrive at Cloud City, they walk down some stairs, and when they reach the bottom, 3PO comes out of nowhere to join them. I'm sure Ady can add 3PO at least turning the corner or something to give us some idea of where he appeared from.
* The lightsabers. Ugh. I know that redoing the lightsabers is a given, but I cannot tell you how frustrated Vader's pink saber makes me.
* Blaster bolts. These too are a given, but there are so many bad looking bolts, troopers that get shot without flashes, blasters fired without flashes, and even troopers with black marks on their armor before they get shot! I also think 3PO deserves to have a bolt hit him, because currently he just explodes without provocation!
* I think Taun-Taun footprints would be nice. Maybe even adding a spray of snow behind them when they kick up their feet.
* The Cloud City elevator. I like the SE shot with the open window looking out at the elevator going past, but after they open the door and Vader is there, it's back to its pre-SE wall state. I'm thinking that maybe just before the SE shot is out of frame, it could fade back to the pre-SE wall, like maybe that's how you close windows on Cloud City. That could also be what Chewie is looking behind them worried about, because why would they need to close the window view if they're just going to dinner?
* Cantina-ize us some Bossk, because he just kind of stands there.
* There are some pretty empty matte paintings of Echo Base from the outside which could better match the action (no X-wings in the hangers, no movement).
* Luke's X-wing goes from mostly out of the Dagobah swamp to almost completely covered in a few seconds. Maybe have the X-wing start to slip into the water when R2 turns to look at it.
* Luke standing up or bouncing back up after jumping after Vader in the freezing chamber has always bothered me. I would just keep that part empty after he jumps because I find that seeing him is unnecessary and distracting.
* If I'm not mistaken, I think the SE bonus hatch on the Falcon that Lando catches Luke through could use better synchronization with the exterior shot of the hatch opening. It seems like it is too far open from the inside shot to have been that far closed from the outside. If that makes sense to anyone but me...
* After everyone leaves Cloud City, R2 stops fixing 3PO to save the day, but 3PO dangles his leg around, a couple shots by the knee and the last shot by the foot. I'd be impressed if Ady could flip the leg around, because 3PO really whips it around in the last shot. It might be easier to flip the leg in the previous shots so that he's always holding it by the foot.
* There's Taun-Taun blood on the wall of Echo Base before Han leaves to find Luke. This is left over from the removed "Wampas in the Base" subplot. I think that the blood could be removed.
That's all I can remember right now. I may add more as I think of them.