I watched all of Makoto Shinkai's past films, so I think I know what I am talking about when discussing his work.
I thought the movie was overall very entertaining, but it lacked the same degree of character development and satisfactory conclusion that his other films had. There is another 3-star review that completely agrees with this exact assessment. Essentially, the problem boils down to Shinkai trying to cram in too many things in one film. For one, going on an adventure to stop calamities happening across Japan is too one-dimensional of a premise to allow the characters to grow beyond what we were initially introduced to. We learn a lot about each character throughout the adventure, but the growth that happen have little to no relationship to the adventure itself. Those growths could have just as easily happened outside of the adventure. Romance was the only aspect of the characters that was directly related to the adventure, but I felt the characters didn't experience enough to develop any sort of romance. It is kind of like playing video games with a stranger online and after a little while you develop a camaraderie, but that is hardly enough for you to profess your love. The supernatural aspect of the film is extremely interesting, but unfortunately the film didn't have time to explore it. A few deities were involved, but we never learn what their deals are, how they came to being, why they did what they did, and a particular self-sacrificing behaviour by one of them makes no sense other than to quickly end the film.
This movie earns a 3-star rather than 1-star because it had good humour. There were numerous occasions throughout the film where people in the theatre laughed out loud. This isn't much of a celebration for Shinkai though, because his previous films had the same amount of laughter. I guess it is good to see that he still has a sense of humour.
If you enjoyed Your Name and Weathering With You, you will find the story in Suzume a bit disappointing. This makes me think that Shinkai is losing his touch, but hopefully he can prove me wrong with his next film in 3 years.