OK just saw this... it's Attack of the Clones not The Last Jedi... the story is salvageable.
First act of the movie is boring and only servers to undo everything that happened in the last movie, if the last movie was properly planned we could have started 1/3 of the way in with Newt arriving in Paris (like how the last movie started).
Newt has autism, my financee has some expertise in that area and she thinks the acting is pretty clearly showing that Newt has it. Not sure if this is a wise idea for a protagonist we need to relate to, especially if the autism itself isn't a big focus so we don't sympathise with him about it.
All of the cameos except Dumbledore are pointless and just serve to cheapen the story. The LeStranges just have a french sounding name and have little connection to Bellatrix who only married in, McGonagal is teaching before she is born for a cameo and one laugh, Nicolas Flamel doesn't do anything alchemical and is somewhat of a Deus Ex Machina, Nagini doesn't do anything and raises lots of continuity questions (she's at Hogwarts... WHAT... does she meet Dumbledore?).
THE FUCKING TITANIC SERIOUSLY!?
Grindelwald is a wasted opportunity, they establish right at the start that he is evil with him murdering the muggle family and ranting about using muggles as beasts of burden. Then at the end he does his speech and presents an alternative viewpoint that muggles need wizard rule for their own good to stop WW2, they did a good job showing why it's appealing to Queenie but it has no effect on the audience because of what we have seen him do. They also made him speak like a villian complete with upper class british accent (wasn't he German in Deathly Hallows?) and look evil with his creepy eye, even retconning that he had it during his relationship with Dumbledore. He should have been handsome and charismatic, the opposite of Voldemort.
Also what are his crimes? Why are US wizards/witches executing people who reveal magic to muggles but imprisoning Grindelwald. Why is he moved to europe... what did he do there?
I started enjoying it about half way in despite the glaring flaws, similar to the Star Wars prequels which I also enjoyed at the time despite the stuff we all tore apart like Jar Jar Binks.
I think I've figured these movies out, it's just a convoluted way to show all the beasts from the Fantasitc Beasts minibook they released years ago (maybe that's obvious?). You think the flashback was to show Leta's backstory but actually it was to show Boggarts again, everything in the story is like this. This entire movie exists only to show Fawkes the Phoenix's backstory, they threw Nagini in there too because that's a "beast" too. The last movie was just to show what Obscurials are. I think each movie will have a big beast reveal at the end (Obscurial/Phoenix) and a mini boss to capture in the suitcase mid way through which is useful later (Thunderbird/Catdragonthing), with a few other beasts scattered around.