|You wouldn't have to reboot the movies. You could reboot from ROTJ onward. As for a reboot being impossible, well, it's already been successfully accomplished with the Star Trek movie. I favor this kind of reboot because it does not wipe out anything from the other reality. It just establishes a different reality. Having been an original Star Trek fan from the beginning, I love the reboot that was done. It's completely revitalized the original story and main characters, and it hasn't done anything for my love of the old series. The same thing could happen for Star Wars.
I also liked what they did with Star Trek, and agree that it hasn't changed my attitude towards the original either.
But the new Star Trek did one important thing which would need to be done in any post-ROTJ reboot: it changed things with a bang, in a major and immediate way. The Narada destroyed the Kelvin, affecting Kirk's life incredibly, and 25 years later it destroyed Vulcan, a bang if there ever was one. These major changes mean that there's no possible way that this new continuity/alternate reality can emulate the old one in a significant way. Sure you can revisit old ideas, and have the occasional character come back, but the Galaxy (and the characters) have changed in such a major and profound way that the same plotlines can't be simply re-done.
Therefore, I submit that only an extreme and drastic change, almost immediately post-ROTJ, could result in a decent alternate EU that doesn't emulate the original.
This change would ideally need to be done within a few weeks of the end of ROTJ (either just before or just after The Truce at Bakura).
By "extreme and drastic change", I mean something like:
-the death of one of Han Solo (Jacen/Jaina/Anakin never born, Leia marries Isolder and so never becomes Chief of State, etc.)
-the destruction of Coruscant (Empire crippled far earlier, NR wins much more easily, strong NR successfully fights back Yuuzhan Vong).
-the entire Empire rallying around one Warlord (Zsinj, or Isard, perhaps) very early post-Endor (Empire defeating the NR, leading to another Rebel movement much later on)
And then it's important to take into account the few parts of the EU that would still happen, regardless of the changed event. I'm thinking specifically of the Yuuzhan Vong. They would still show up, since they're almost exclusively extragalactic until Vector Prime. Surely Nom Anor and the other spies would warn the Vong fleets about a stronger Empire or New Republic, or maybe the Empire under Isard would have found those spies long ago, but that doesn't change the fact that the GFFA is the Vong's Promised Land. No reboot would change their arrival, only how they're dealt with.
Can I just say: I really like the Infinities comic miniseries. How they took each film, changed one detail that was beyond anyone's control, and you saw how things continued from there. My three ideas above can be applied in much the same way:
-Random mechanical failure causes Millennium Falcon to stall while in battle at Bakura; Han Solo dies as a result.
-Wife and children of a Maw Installation employee are killed by random happenstance (I'm thinking botched robbery); employee goes crazy, steals Sun Crusher, blows up Coruscant.
-Extremely prominent Imperial Officer is able to escape Endor (whereas normally he would be killed). He has fame (like Soontir Fel or Maarek Stele), charm, and can rally a crowd. He throws his support behind someone like Isard or Zsinj, and urges the entire Empire to do the same. Isard (or Zsinj) is named Empress (or Emperor).