Though the original source material for Howl's Moving Castle was decidedly Western, the film adaptation is very un-western in cinematic taste. At the beginning of the movie, the main character turns into an old woman without much of a reason for it, whereas Western audiences would more like to believe such a dramatic transformation should only happen to those who deserve it (Beauty and The Beast being the prime example). Even professional critics regard Howl's Moving Castle as Miyazaki's weakest film. No matter the visual fidelity and strength in the animation, the story is often times confounding, and like some of Miyazaki's more contemplative works, there is no central thread along which the film stands. Chihiro has to find her parents. Kiki has to learn and train to become a witch. Sophie has to... become young again, and Howl needs to... I still don't know. When compared to Nausicaa, or his crown jewel Spirited Away, it's insane to think that the director spent decades of his life to go from being so bold and assured with his first epic to becoming so loose and disorganized so late. While Miyazaki claims the film as one of his favorites, to portray the message that life is worth living, I'm not so sure he succeeded in delivering that message universally. In contrast, everybody who watches Spirited Away knows the story is about a little girl who needs to grow up and learn to be more self-reliant.
The majority of western cinema centers around that purpose of the plight of the main character, the hero's journey, and the arc they travel through. Or at the very least, you will find that structure in the West is much more rigid and praised. Some popular Eastern films including Bruce Lee's wuxia films forgo plot structure and instead focus on the immediacy of the events and characters, focusing not on what could be or what should be, but on what currently is. Plot does not strangle the story. This stands in sharp contrast to Disney's more modern fantasies. There are certainly exceptions, but if Spirited Away is the most structured of Miyazaki's work, it will be praised in America for being so loose and flexible in its storytelling, allowing for serendipity without the expectation for perfect dialogue and "speech-givers."
Howl's Moving Castle follows that Eastern tradition of living in the moment, and not being too concerned about a structured plot. Things happen: Sophie turns old by a witch, the wicked witch turned into an old hag with dementia herself, a reigning queen tried to kill Howl and Sophie by suspending them in mid-air, rules come up that are not explained, Sophie turns young occasionally for no apparent reason, the fire demon residing in the castle made a promise to Howl and we don't know what, everything comes crumbling down, and we should just accept it. It's not an easy film for Westerners to just accept. At least Princess Mononoke and My Neighbor Totoro and Ponyo and Porco Rosso and Nausicaa had a fully resolved happy ending. Howl's Moving Castle has nothing that you can firmly hold on to. If you ever watched it, you should know it has a very high bar on entry.