This is NOT a Miyazaki film
I am always pissed to find that a lot of people praise this because it's a film directed by Miyazaki. First and foremost, this is a LUPIN film. This is not part of Miyazaki's canon of works. The only reason people are recommending this film is because Miyazaki's work has been getting recognition, thus reaching this caper film. Everybody thinks that just because Miyazaki has directed this film thus makes this a Miyazaki story. This is not so. The only stories Miyazaki wanted to tell demanded high-quality animation and standards, and unforunately, Castle of Cagliostro is lacking what Studio Ghibli has done. The only reason Cagliostro was created was because the company that made the Lupin series demanded another Lupin movie, much in the same way that Pokemon and Yu-Gi-Oh needed movies.
People have been praising this film, because Miyazaki just so happens to take the role of director. Don't be fooled from all this. Castle of Cagliostro is a LUPIN film, not a MIYAZAKI film. Or in other words, this a LUPIN III movie in which Miyazaki happened to take the role of director. A Miyazaki film is when the concept is completely written and fully storyboarded by Miyazaki himself, and that includes Whisper of the Heart. So just think of it this way, if the movie is released by Disney and it has Hayao Miyazaki's and Studio Ghibli's name slapped onto the back context, then it's a Miyazaki film. (Whisper of the Heart is a Miyazaki film)
There is a reason why Manga Entertainment distributed Castle of Cagliostro and not Disney. It's because Tokuma-Shoten did NOT publish the work. Miyazaki's stories demands high-quality animation, and the only way to achieve that was through the funding of Tokuma Shoten. Unfortunately for Castle of Cagliostro, they only made the film for other purposes.
People have been exposed to Hayao Miyazaki so much that they mistake this film to be part of Miyazaki's canon of works. They just don't know how the system works. For those who are thinking of purchasing this film because Hayao Miyazaki's name slapped on the top of the box, just say to yourself that it's NOT released by Disney. Period.
Oh, and also, there is a reason why Amazon.com has released a Miyazaki 6 Pack instead of a 7 Pack.
EDIT: A more updated take on this:
http://imdb.com/name/nm0594503/board/inline/31300796