I'm feeling too lazy to link the post, but Alan Moore did work on TTL's post-Crisis reboot of Superman, which included elements of OTL's
Supreme. That said, it would be an intriguing proposition to have him return to the Man of Steel around 1996 to revisit those themes and perhaps incorporate elements of Grant Morrison and Mark Waid's
Superman 2000 pitch. It could function as an "apology" for his part in inspiring the excesses of the Dark Age.
It should be worth noting that TTL is approaching DC's
Zero Hour, so to speak, which could give Moore an opening as the event creates another "revision" that changes the Man of Steel's history. For one, editorial mandates and rampant retcons forced DC Comics to reboot the
Legion of Super-Heroes so Moore could rewrite them back into greater Superman mythology. This might be a bit controversial, but what if said revision reestablished Superman's Golden Age history? (To an extent.) Superman could be the first public superhero who had adventures with the Justice Society of America [1] while Lana Lang was his primary love interest at this time. Similarly, the Ultra-Humanite could take Lex Luthor's place as his primary antagonist from the 1940s to the late 60s while Clark Kents works at the Daily Star under George Taylor. Meanwhile, his kryptonian genes and constant exposure to Earth's yellow sun made him immortal and ageless while Lana grows older. This realization, combined with the Ultra-Humanite's (apparent) suicide, prompt him to leave Earth to explore the galaxy.
I'm glossing over several story points, but Supes eventually returns to Earth to help inaugurate the "modern" Age of Superheroes. It wouldn't completely invalidate the stories that occurred from 1987-92, but tweak/"revise" certain details. I just need to figure them out. Anyway, that's all that comes to mind now.
[1]Perhaps the OTL Byrne retcon of Hippolyta going back in time to become the Golden Age Wonder Woman can work its way in here as well.