Well, here’s my wish list. This includes things that probably are outside the realm of feasibility. It also includes a few things that are available via TMWNN’s v1 of his Devastator edition.

Mos Eisley entrance - as much as possible to work with. The SE shot with the mirrored troopers sans extra pair of troopers, rat, or robot. The shot with the Jawa swinging from the Ronto, with those removed to be the original shot with the SE background. (I like how my cut has this sequence but it could be better.)
The SE scene where Luke reunites with Biggs has R2 jump upward where they removed some lines. Since it’s a SE inclusion it’s a prime target for improvement. Adywan has done this already, so when it’s released in HD I may cull this from that.
Make R2’s blinking red/blue light work, as the original prop was broken. Adywan has done this but his will be the 2011 source. TMWNN has done a lot of this, but not the trickier shots where there’s a lot of motion.
Removing Yavin IV from the first shot of the Battle of Yavin. Adywan has done this also, so perhaps when Revisited appears in HD.
That one weird shot where Vader has been brightened in the Death Star hallway. I believe Dat_SW_Guy has done this.
The Falcon needs its radar dish in its first appearance.
The crap Alderaan image out the Death Star window, as fixed way back by Darth Editous.
TMWNN’s version of the droids outside the cantina spotting troopers, removing the foreground CG dewback but leaving the background one.
Remove extra vaporators in a SE wide shot of the sandcrawler parked outside the homestead that disappear later (or add them to that shot).
Use TMWNN’s or Dat_SW_Guy’s Alderaan explosion to avoid the added shockwave I don’t like.