Sam Williams’s review published on Letterboxd:
You'd think the 10th best selling fiction author of all-time could manage to write a better screenplay than this. It's incredibly slapdash and completely lacking in inspiration. It feels like Rowling doesn't even understand the rules of her own world. And I'm not talking about the rules of the magic. Those have always been fluid to the point of meaningless. I mean the "wizarding world" itself. The bureaucratic structures, cultural customs, and social mores are poorly defined and shift wildly with the whims of the plot.
Ostensibly, our intrepid heroes are trying to stop wizard Hitler (No, not Voldemort. The previous wizard Hitler.) from being elected Supreme Mugwump. This raises questions such as "What is a Supreme Mugwump and what power do they wield?," "How is a Supreme Mugwump normally elected?" and "How does being elected Supreme Mugwump help wizard Hitler Gellert Grindelwald accomplish his larger goals?" Rowling and Yates are uninterested in providing these answers. There's no attempt at all to reach anyone who isn't already a frothing at the mouth Potter nerd willing to gobble up Rowling's every utterance as manna from Heaven.
The film opens with Newt attempting to save a beast in a perfunctory nod to the title. The importance of this beast isn't explained at all until the third act for no real reason. Next, Newt gets the band together and sends them out on missions for Dumbledore. We're told that there's some obfuscation needed because Grindelwald can see the future, but it doesn't really make any sense that he could see them discussing the plan and letting the audience in on what's happening but can't see Dumbledore sending messages to each person.
Senegalese-French Yusuf Kama, introduced in the last film as the brother to the fridged Leta Lestrange, is sent to join Grindelwald's team. Grindelwald, rightfully assuming that he's a spy, removes his memories of his dead sister. That seems really sad and important to his character! Nope. Never mentioned again. We also never see him send messages back to Dumbledore or do anything that spies do. He's window dressing at best. Then there's Newt's assistant Bunty who's big task is paying someone to make some suitcases. Newt and Theseus are sent to ask a guy nicely not to support Grindelwald where Theseus is arrested and disappeared to a secret prison for no real reason. And let's not forget comic relief no-maj Jacob Kowalski who we're repeatedly told is the best person in the world. His entire purpose seems to be to serve as a decoy and hopefully win back Queeny. Cool. Jessica Williams is there as well doing a terrible mid-atlantic old timey movie accent and nothing much else. No one has an arc. No one has a real personality. There's just nothing there.
The side plot centers around Ezra Miller's Credence. Credence was built up as a powerful force in the previous film only to be completely wasted in this one. There's no way to adequately explain how bad his storyline is without spoiling it, but it's incredibly pointless and Miller glowers and mumbles his way through it with zero passion. They want him to be Anakin Skywalker, but even Jake Lloyd was more convincing. Also oddly passionless is Mads Mikkelsen as Grindelwald. I'm not part of the #JusticeForJohnny Army and I think Mikkelson is a better actor than Depp at this point in their careers, but at least Depp brought some menace and flair to the role. Mikkelson is on autopilot, his Grindelwald charisma-free and not remotely scary. Jude Law fares a bit better as Dumbledore, but only a bit. Redmayne is still doing the autistic Hugh Grant thing with ever-diminishing returns.
I wasn't high on the first nor the second film in the series, so it's no surprise that I wasn't on board for this one, but I feel like even the diehards have waning interest at this point. The series is floundering and it's time to Avada Kedavra it out of its misery.