It's a bit of a mess, but a fun mess. Which isn't surprising given that it was in development hell for over a decade and featured a long list of involvement from American and Japanese animators/movie-makers [including Hayao Miyazaki and Isao Takahata, George Lucas, Ray Bradbury, Gary Kurtz, Edward Summer, Osamu Dezaki, Andy Gaskill, Yoshifumi Kondo, Brad Bird, Jerry Rees, Chris Columbus, Moebius, John Canemaker, Ken Anderson, Robert Towne, Brian Froud, Frank Thomas, Ollie Johnston, Paul Julian, the Sherman Brothers, Masami Hata, and William T. Hurtz].
It's probably a bit of a miracle that it turned out as good as it did.