Interesting point, yes - the central characters are constructs who enable the exploration of the actual character in a Murakami novel, which is basically the weird, weird world. Murakami's world is a trickster magician with a multiple personality disorder.
(And I typed that whole comment writing "Miyazaki" rather than "Murakami", which shows you how eager I am to get my hands on Howl's Moving Castle).
Re: uniformity
(And I typed that whole comment writing "Miyazaki" rather than "Murakami", which shows you how eager I am to get my hands on Howl's Moving Castle).