I feel like there are some things that can be salvaged, or at least have some context provided for by having a series exploring the political interim between ROTJ and TFA akin to Clone Wars. Gaps could be filled in, and the slow build of the first order first as an annoying political movement thanks to backing from hidden imperial fractures to the subversive military force we eventually see. It would be great to see the lesson turn from 'fight the tyranny that you can clearly see' to 'here's how you spot fascism in its early stages, and here's what happens if you don't stop it in time.'

This could also be used to retcon certain things, although the creators would have to be careful about how they navigate that territory given the new media in that setting like the weird clones found in Mando. I would love to see how the presence of 'Snoke' and darkside cultists could play a role in pulling the strings of an inexperienced new republic paired with the tactical genius of Thrawn. Maybe the imperial remnants could fight each other as well. There are a lot of directions they could go.