In many ways, this movie feels like elaborate scene setting instead of a proper first installment to a new franchise.
I really, really liked Fantastic Beasts, but the above line is right on point. It's a beautiful film with great character work, but the plot itself left me wanting more.
There is almost too much going on in this story, and it makes it hard to grasp onto any particular thread. There are at least 3 stories going on in concert, but they weave in and out of each other in a way that just felt muddled to me. Each story is good on it's own and the actors do great work, but it just doesn't gel the way you'd like a great movie to come together.
I was happy to jump back into the Harry Potter world, and it was wonderful to see another film in this same universe, but with zero returning characters or locations. The Harry Potter films created one of the most delicious movie universes of our time, and Fantastic Beasts continues that legacy well. Everything is familiar, but distinct. It's exactly what you want from a "universe" story, and that's what Fantastic beasts nails.
Chris Columbus's first 2 Harry Potter films were not great, but they had amazing bones; actors, world design, music (my god, the music!). The first Fantastic Beast film is better than either of those first 2 Harry Potter films, but I think it accomplishes the same basic goal. It's a starting point that future films will build off of, and I think it's only going to get better.