In TPM there is a shot of the crowd and a shot of Sebulba at the start of the race that were cut for the DVD. Also, the transitions during the brief extended speeder trip after they reach Coruscant are different. Both these areas don’t exist in HD. The earliest HD broadcast is of the DVD version where these changed were first made.
In A New Hope, the speeder entering Mos Eisley, the Greedo shooting scene, and Jabba the Hutt were all changed for the DVD.
You may be right about Empire.
In Jedi, the only section I can think of is the end Celebration where they added Naboo and changed Coruscant.
All the other changes between the 97 SE versions and the DVD/Blu-ray can be pulled from the 35 mm scans.
TeamBlu is about to release their scans of the 1997 SE of the original trilogy. Harmy used theirs as a source for his Respecialized Edition of ANH. Maybe we’ll see what turns out with Empire. If somebody is able to crop out some shots and possesses good editing skills (not me), it seems possible. We can use the Blu-Ray as a primary source, and as far as I know, not much editing is required, but just to replace some shots and reinsert the old visual effects. Would be a lot better if we can have access to You-Too’s (sorry if I spelled his username wrong) colour corrected version, I presume is in 1080p. And last but not least a high quality rip of the theatrical Audio Track and laserdisc mixes. Shouldn’t be that hard. At least compared to the effort put into the Despecialized and '97 Respecialized Edition. Sorry if I’m trying to be too much of a smartass.