Spoilers in this thread for FB3. Beware!

I saw it this afternoon, my thoughts below.

Overall

I enjoyed the film, but I suspect much of my enjoyment came from being an HP fan. Someone only casually into HP would not enjoy it nearly as much, I suspect, because plot and character problems persist.

Still, it's a better constructed movie than Crimes of Grindelwald on that front. Mads Mikkelsen is an excellent Grindelwald and you just wish he had been in the role from the start.

But even as an improvement on Crimes of Grindelwald, and even as a movie I subjectively enjoyed, it's definitely not up to the standard of a well-told story.

Set-up

The storyline is essentially Grindelwald's plan to become the next leader of the ICW. He plans to do this by gaining control over a Qilin, a magical animal which can identify those who are pure of heart, and which was historically used by wizards to choose the leader of the ICW (the word "Mugwump" appears to have been quietly sidelined). Although the Qilin is no longer used, and there is now an election process (more than that below), having the Qilin bow to you carries great weight in persuading people to vote for you.

There are the fundamental elements of a good political story here. Two establishment candidates, part of the elite and having the support of the political classes, but resented by the disillusioned common people. A third party, populist candidate enters the fray, one opposed by the established elite, but with the love of the common people. It's a story with a lot of potential and relevance.

However, FB3 doesn't do the groundwork or spend the time to do the political story justice. For example, the 2 establishment candidates, Santos and Liu - we know absolutely nothing about them. We don't know what they stand for, what the issues between them are, what they are like as individuals, or who they are associated with. We don't even know anything about the countries they come from.

Similarly, the election process is pretty vague. We don't know how it is performed. It seems to be some form of popular vote but it's not clear if everyone in the world votes or just the people in attendance at the ceremony as representatives/electors of the wider people. We don't know what powers the leader has, once elected, or what their relationship is with the national Ministries of Magic.

Because none of this stuff is developed, the story comes across as very shallow.

Character

The other problem with the plot is the role of the main characters in it. Simply put, the characters spend most of the film doing nothing. There is a moment quite far into the movie, probably around the end of the second act, where Perseus comments that they have achieved nothing and are back where they started, and he is absolutely right. All the movie up until that point is just the characters being shuffled around the board to observe the plot being performed by other people.

The things they observe may well be interesting to HP fans keen to know more about the HP universe, but it's not a story which gets you invested emotionally or which the characters have any agency in.

In terms of character arcs, it feels like the main arc of the film is intended to be Dumbledore firmly positioning himself as opposed to Grindelwald. Plotwise, this character arc is symbolised in the breaking of the blood pact.

The film starts with a strong scene on this front, Dumbledore and Grindelwald having tea in a Muggle restaurant. That scene is probably the best in the film and should have been longer. After that, the character arc loses its way somewhat, especially at the end.

There are two problems in particular. Firstly, a big part of the presentation of Albus in the film is in showing off all his flaws - the fact that he was an actual believer in Grindelwald's cause, its joint progenitor, as well as the fact that he is to blame for Ariana's death. But the film concludes with the Qilin bowing to Dumbledore, showing him to be unusually pure of heart. This feels unearned and like it contradicts his character arc in the film of being flawed and having to learn to move past it and try to do better.

Secondly, the breaking of the blood pact, which should have coincided with the climax of Albus' character arc, feels random and tacked on. It happens due to a magical technicality with no character importance. A real misfire.

Resolution

I felt like if the studio had more confidence in the series, then this would have been the perfect opportunity for a cliff hanger - an "Empire Strikes Back" moment where the bad guys seem to have won. You could have had Grindelwald's plan succeed and him take control of the ICW, causing wizards to split down the middle between those loyal to the ICW and Grindelwald, and those who oppose Grindelwald and feel strongly enough about it to act as outlaws.

But ultimately, I think they were too afraid to take that route with the film. They wanted to give it an ending that would work if the film flopped and there was never a FB4. So they tied everything up neatly, but in doing so the ending was a lot more twee and unimpactful than it could and should have been.

The lack of impact also ties back into the lack of set-up. The primary plot climax is the true Qilin being revealed and selecting Santos - a new tertiary character we know nothing about, and have no emotional investment in. For a moment, I had thought it was going to choose Jacob, who is repeatedly emphasized to have a good heart. That would have been a real turn up for the books and caused political chaos. Then I thought it was going to pick Newt, which I would have liked less as it feels like Newt's character is already being pushed beyond his natural role in events, but at least it would have made sense in that he is consistently depicted as unusually honest and good-hearted. But no, the Qilin picked Dumbledore - which is bad for the reasons above - and then a tertiary character. And that was the climax. It just fell flat for me.

Worldbuilding

The stuff I liked best about the film were the hints we got as to the politics of international wizarding society. The entire sequence in Berlin was great - the allusions to political players running schemes, to old histories between the personalities at play, including their relationships with Dumbledore, the way the German Ministry ends up falling to Grindelwald and Grindelwald using that to establish himself as a legitimate candidate in the ICW election. All good stuff, but - tying into my above point about shallowness - only ever hinted at. This all needed fleshing out so much more.

The major worldbuilding misfire is the dueling, I think.

Throughout the film there is a feeling that you're just waiting for Dumbledore to let loose. It's almost palpable, the sense in which he is barely restrained and you're constantly waiting for the moment where he drops that restraint and we get to see what he is truly capable of.

But while he does engage in combat a couple of times, it's never a full duel. Indeed, they seem to have invented a new dueling mechanic for the sole purpose of reserving the "Dumbledore is awesome" moments for later movies. That mechanic being some kind of parallel world in which duels take place, where they can occur without causing any real damage to the environment or bystanders. Duels without consequence, basically.

Perhaps this is supposed to be a visual metaphor for a contest of minds via legilimency. If so, it's very ambiguous. None of this is ever explained - it's never even really acknowledged that something different or unusual is happening. It's all very odd.

Relationship with Crimes of Grindelwald

One thing FB3 does well is that it rows back some of the worst sins of Crimes of Grindelwald. Credence has been sidelined so that he won't be a major player in future films. The Dumbledore backstory for Credence has been made more sensible, and his power level has been contained such that he could never challenge Albus.

Queenie has been given greater character consistency.

However, all that rowing back does make Crimes of Grindelwald an even more pointless film. It's the Star Wars sequel trilogy again - a lack of proper planning meaning they have to waste time in later films to undo earlier ones.

In retrospect, film 2 should have set up a lot more background for Grindelwald's movement, the ICW election process and the candidates, rather than wasting a whole film on a boring mystery about the parentage of a character we don't care about.