Rey's lineage was a hole that did need filling though. It did. Making a big fuss about the mystery of who she is for nearly 2 movies, only to unceremoniously drop it and never have it explored again...I do not think that would've been good storytelling. I mean, sure, it's a major subversion of a classic Star Wars trope. That doesn't make it an inherently good story. TLJ also did nothing with it. Imagine Kylo and Rey never had the "nobody discussion", and he simply tried to lure her to the dark side. She refuses, they destroy the lightsaber and everything plays out as is. It literally has no any bearing on the rest of the film.
I do not have a problem with the "nobody" reveal in TLJ as a thematic beat and a red herring mind you, I think it works to push Rey to accept thats she must define herself rather than a bloodline. It was also a good way to reveal that she's NOT a Skywalker and something is 'different' about this story. But more context is needed than that. Otherwise it just feels like you messed with the audience's expectations for the sake of it. And I've yet to hear a coherent argument as to why someone from obscurity emerge as the hero of the Skywalker Saga works as a good ending for the saga that bears their name as a whole. Even the Palpatine thing, while controversial, at least that has a layer of dramatic irony to it. The Skywalkers take in the spawn of their enemy and show her love and guidance, and ultimately defeat him. The opposite of what he did to Anakin. There's some poetry in that. Rey being a nobody just feels like a non sequitur. Mythologically, I don't think it flows. It feels too meta.
As for Palps....well, yeah. The ST had a major villain/reason for existing problem from the the very beginning. Particularly when you're trying to follow up on a story that had a satisfying ending and wrapped things up rather neatly.
It all just comes down to the fact that TFA didn't lay the best foundation for the new trilogy. TLJ kind of just sidestepped that and tried to tell a good individual story (I don't blame Rian for that), then TROS was left with a LOT to reconcile but didn't embrace making a robust film to do that. I would've liked to see more Supreme Leader Kylo Ren, but he was never going to be enough to carry weight as THE villain of the entire saga. He was too conflicted, we'd seen him in too many vulnerable moments. Redemption was always a distinct possibility for him, being the last Skywalker. Rian even recently confirmed that he saw Kylo and Rey as having a romantic connection, so he probably saw some sort of redemption in Kylo's future too. You needed a true villain. Let's face it, you needed the Sith. Maybe it could've been Maul instead of Palpatine like in one of Lucas' treatments. But you needed some remnant of the Sith.
Again, mythologically....why tell 6 films about an overarching conflict between the Jedi and the Sith. And then a final 3 about....what? The Jedi vs. ...Dark Side Users Who Behave Exactly Like the Sith But Technically Aren't Sith... Because Reasons...? That is so sloppy and uneven.
Like it or not, Palpatine's return was a clean solve for a lot of the foundational issues of the trilogy, almost obvious in retrospect. Everything about the First Order was simply trying replicate his Empire, anyway. It's a shame they didn't execute his return better and we're left with what we got, but I am just trying to draw attention to some of the glaring issues with this trilogy's setup. I like that TLJ just did its thing and tried to just be a good movie on its own terms, but this trilogy was backed into somewhat of a corner from the moment it employed the mystery box formula. A third film was always going to have to reckon with that.