It's a weird question to me, because a good series can take anything and keep it going. Even things that most certainly should not have been kept going. HBO's Watchmen, for example. The comic really should not have had a sequel. It was not meant to have a sequel. Creating a sequel forces the writers to answer the questions that Moore explicitly did not want to answer and instead leave to audience interpretation.

But they made a sequel to it anyway, and it was great. Took the ideas and went a whole different way with them.

So, can a good series happen in the wake of the Sequel Trilogy?

Sure.

There's that little thing about Troopers being kidnapped as children and forced to fight, which was a plotline that could create a lot of nuance to the troopers that was for the most part ignored about 10 seconds after Finn left the Order. You could make a great show about that.

There's the remnants of the former Republic trying to pick up the pieces after their government was blown up. Not every important senator was on the planet. And not every allied planet would so meekly cower beneath the Order's boot. That could be a story as well.

There's also, I guess, technically, some time between 8 and 9. Maybe a year or two of open conflict as Kylo tries to consolidate his power. I could see that being a story, even theoretically a good one. Just not one I'd want to see explored. I've basically had enough of Kylo. But then, I had enough of Ani before Clone Wars came out, so who knows?

But after all that... why?

What about the sequels is worth holding on to? I guess there's a message there about the rise of fascism through the children of those who defeated it. I guess that could be an interesting string to pull. But... that's really a stretch.