A little too surreal
It is often said that the difference between fantasy and surrealism is that fantasy "makes sense." It is encapsulated within its own world that is run by certain rules, and logic.
However, I found that this film used a lot of imagery that was not well explained or tied into the plot and the overall fantasy theme. Usually Miyazaki is great with creating an airtight seal around his fantasy worlds, but this movie raised a lot of questions.
My explanation is that the movie had to leave out a lot of things that the book explains. And reading the synopsis of the book confirms my theory.
In the film, there were a lot of things that may seem "cute" at first but overall feel uncomfortable when trying to fit them into the grand scheme of things. For example, I couldn't comprehend how "silly" a lot of the characters were. I think Miyazaki genuinely hates the concept of an irredeemable "villain" so he had to make characters like the Witch of the Waste silly and ridiculous in character even though she started out as a very malevolent being.
I found Howl too "Willy Wonka" like. Yes, he uses his charming demeanor to hide his inner pain but I found that he just behaved a little too ridiculous overall. And there are things in the film that are not well tied into the plot, like Howl flying around like a scarecrow in a warzone (part of a war that is not explained) killing off magical beings. It's almost like he does it for fun.
Or even Suliman, who has a very "lawful neutral" demeanor and we are never really sure if she wants Howl dead or not? She doesn't seem to care either way in the end, and neither does she seem to care about prolonging the mysterious war that she has waged.
Overall, this film seems to be more like an Alice-in-Wonderland acid trip for Sophie instead of a magical adventure. There were too many things that we just had to take "for granted," and a lot of non-sequitur narrative that just seemed to go everywhere. I found that there was not a lot of opportunity to really grasp the gravity of the themes and characters and how it is all connected. The film seems to treat it all as a big joke with a happy ending. Because it is a children's movie? I don't know.
But I won't let all of that take away from the fact that this film is beautifully done.