The movie was enjoyable, but the plot was simply nonsensical to the point of disrespecting the franchise. What made it bad:
* We learn nothing about Dumbledore that we didn't already know.
* We get legitimately zero scenes of romance or connection between Dumbledore and Grindelwald (which makes their "love" completely unbelievable).
* You could cut out half the main characters and the plot would remain intact. Not sure why there were so many characters that essentially just stood there and made quirky remarks.
* Almost every scene either contradicted cannon, defied laws of the wizarding world, or repeated plot points that were already made clear (the plot is so simple I'm not sure why they would need to repeat anything).
* The plot was extremely weak and unbelievable, to the point where at times it didn't even make sense.
* The writing/screen play were weak. You could swap character's lines and the outcome would be roughly the same.
There's more to complain about but let's stop there. Here's what was good:
* Lots of cool looking magic and some cool new beasts in the film.
* I laughed out loud 2 or 3 times (not including when I was laughing at how bad the plot was). There were some good/cute moments that in many ways "saved" the film.
* It was directed well in terms of creating atmosphere, drawing dramatic tension, etc. Some really good "best picture" shots and CGI.
* It's a harry potter movie, so at least there's more content.
Overall this is a clear 2/5. I didn't walk out, but I wouldn't watch it again. It didn't make me feel anything for the characters, and the story was poorly told. I enjoyed watching it for 2 hours on a Sunday night.