A lot of great points here, and I especially agree that it might’ve been more interesting and believable if Finn was more of a soliderish jar-head, who has to de-program himself as a civilian. I thought Finn in The Force Awakens was a breath of fresh air and a very different character in the Star Wars universe, and John Boyega brought a lot of charm and energy. However, it seems there was no secret plan for how his character would develop, or how he would fit into the story, so Rian Johnson just dropped him. What a bummer.
But I keep seeing – and coming back to – your first point, which really sums it up. The Last Jedi is actually a fine movie: it’s flabby, needlessly convoluted and a bit messy, but it just about works as it’s own thing. Where it completely fails is as a chapter in the overall Star Wars saga. Sadly, it really needed to tick both boxes.
So long as you don’t care about any of it making sense, logically or thematically, or give a shit about any of the existing characters or events, then yeah, it’s fine. The problem is that we all really do care about that stuff.