Well, having finished the novel ... I can state categorically ... that both batman and johnny soko are right for the character Howl.
Howl is a ladies' man, a lothario, a love-'em-and-leave-'em heartbreaker, and a sexified con man. If sexy means androgenous boy to the Japanese (and to Cadaverous Pallor), then that's what's required for the Nipponese version of Howl. But that would simply NOT work for American audiences, and so I believe the husky batman voice was appropriate for the dubbing.
Now that I've read the book, I have 10 times more admiration for the Ghibli movie ... which invented practically everything other than the basic characters, their basic situation, and a few of the events that take place inside the Castle.
The Ghibli version invents the war scenario ... which I found so hamfisted. But that's comfortably grounded compared to the Ugh factor of the novel when ....
Wow, Ghibli invented practically
everything for their version of the story, including ...
But, overwhelmingly, I prefer the movie version of the story. Not since Disney adapted Pinocchio has an unwieldy piece of children's literature been so vastly and (imo) successfully molded into an animated film.