As a potterhead I was not satisfied with this movie. It lacked character exploration. I was looking to explore the character development of Nagini, which also disappointed me. Movie looked really pointless to me. Story was really not convincing as for the character so much important as Grindelwald.
Expectations were high but delivery was poor. Really good use of CGI but that's not what I was looking for. Critics are right. I would recommend you to avoid watching this movie but if you want to watch don't keep high hopes.