Oddly enough, perhaps the part which makes me most envious here is that ST in this show not only got to do a war storyline like DS9 ended up being, but that with every other aspect (like ultimately pulling a Decon Recon Switch on how this impacts the tone, probably averting the Tough Act to Follow of the latter show IOTL) we get a storytelling thread I’m increasingly loving: depicting the aftermath of a massive conflict and how the world is rebuilt, specifically within the original story and not some other media continuation(s). I cannot stress this enough; much as I love getting a big climax to the conflict at the end, I love all the more when the story opts (for whatever reason, perhaps even a Post Script Season) to show that post-war difficulty and adjusting to the changed (for both worse and better) world… it makes me hunger all the more for this within the media I consume, be it literature, live action [tv/film], animation, or even video games (and no, the “big” conflict ending doesn’t mean “no conflict”; look at Suikoden II for an example of a game story that defeats the Big Bad around 2/3-3/4 of the way through, yet still makes a more personal and viscerally-satisfying climactic conclusion in that last stretch!)
I also appreciate this kind of alt Star Trek exploring the aftermath of a huge war like this. There's lots of opportunities to vastly expand the worldbuilding of Star Trek that might not even be possible OTL with the lack of follow up from DS9's Dominion War arc. I'm sure that Trekkies will find it very surprising that instead of exploring strange new worlds in the frontiers of Federation space, it's within Federation space or in the Klingon Empire/Romulan Star Empire, and the like. Of course, I think once the sequel series ties everything up and the UFP returns to normal, they'll return to something similar to the standard format (like with alt Voyager), but it's an interesting reprieve that gives writers a lot of potential for new stories within the world of Star Trek.
Again, promising; also leaves things open for a more successful franchise later, as opposed to the life support it got put on in our 2000s (thanks to both the “not-actually-tenth-because-Galaxy Quest” movie, but also ENT with their completely-rubbish attempt at a Fully Absorbed Finale!)
Spacing TV shows and movies in a timely manner could avoid the huge franchise fatigue that doomed the TNG-era of Star Trek, which is ostensibly a good thing.
And tbf Lucasfilm does have more successful non-Star Wars franchises ITTL so George might not feel as trapped by SW as he did OTL and thus have less incentive to get something out (which would be a massive change in and in of itself)
Honestly, I think Star Wars prequels (and sequels) are far more likely eventually than not. It was a proven box office draw and the supposed 9-movie plan was well-known by at least the mid-1980s, so there was definitely a kind of expectation or hope that there would be more episodes eventually. If Lucas dies at any point, sells the film rights for any reason, or just needs money, more Star Wars is pretty likely. Of course, these movies are not likely to look anything like the ones IOTL except perhaps in broad strokes.
I was genuinely surprised that Geekhis retconned the confirmed release of the Prequels since the year was the same as OTL and gave a lot of leeway towards how the Prequels could've looked like. A shame, but I understand his reasoning.
As for the viability of the Prequels, it's actually likely that George Lucas might not be interested in making the Prequels or the Sequels, not only because of Willow, but because of other film franchises like Dinotopia if he ever decided to adapt it. At that point, he's simply too distracted to write such a massive story, and considering his desire for creative control, he's not going to try and lease it out to other writers so easily, even if it meant Star Wars stagnates. He's not a man beholden to Star Wars unlike OTL.
Honestly, if you REALLY wanted to kill Star Wars, you could just butterfly the EU, here and now. Remove Dark Empire and the Thrawn Trilogy (along with the possibility of new SW material) and it's very likely the revitalization of the franchise will be halted and it remains dormant. The franchise dies a very slow, painful death as people move on to franchises like Ringworld, Star Trek, Babylon 5, or even anime like Gundam or Evangelion once those arrive in the states. The OT is still the OT and people will still remember it fondly, but Star Wars wouldn't be the media juggernaut it is now if George Lucas and Lucasfilm don't care about the franchise anymore.
However, I find it to be highly unrealistic, if only because the OT was such a huge cash cow that Lucasfilm might be interested in releasing new material anyways and I don't think George Lucas would reject the stories that Tom Veitch and Timothy Zahn came up with. In that case, I honestly think George Lucas should just give up trying to make stories for himself and leave Star Wars entirely to Lucasfilm and the EU if he's distracted by multiple franchises. That includes the Prequels.
Also, I'd find it to be insanely ironic if Marvel got to release all of the SW EU comics like Dark Empire or Disney Publishing through the Thrawn Trilogy. In that case, fans would praise Disney for saving Star Wars instead of destroying it OTL with the Sequel Trilogy and the removal of the EU.