Crimes of Grindelwald is complex, intricate, and breath-taking. That being said, it does spend most of its time setting up for the rest of the series (and doing backstory for HP stuff). That being said, it's not a sloppy film, and its only overburdened for those that are not very familiar with the HP series.
The critical reception for this movie is similar to what it would have been if the HP books had been more faithfully adapted with all the characters and details included. Instead, they were simplified and plot lines and characters were cut entirely to "fit" what makes a "good" movie. Well, Rowling is at the helm more this time, and those details and plot lines and characters she created for this story remain in the film.
Basically, imagine that the filmmakers behind Half-blood Prince left in all that "unnecessary" stuff about the Gaunt family in the movie... or that things like S.P.E.W., apparition classes, the Deathday Party, Peeves, most of the explanation behind Snape being the HBP, Harry throwing a fit in Dumbledore's office after Sirius dies, etc... That is what Crimes gives us-- a Wizarding World story that doesn't shy away from details and plot lines that are what make Rowling such a brilliant creator.