(There are no spoilers below.)
Coraline is a catalog of wonders. It has enough imagination for five feature films. Unfortunately, it only has enough story and characterization for a half hour special.
While Henry Selick is a very gifted art director and director, he did himself no favours by writing the script. His understanding of story structure, scene construction and characterization is extremely weak. The plot takes forever to get started; the film relies on a parade of imaginative visual ideas to hold the audiences' attention until that point, but I found myself losing interest.
Once the story does get started, the villain is poorly motivated. While the villain wants something, she has possessed it in the past and repeatedly abandoned it. There is no explanation for her previous loss of interest or why she wants it again. The film's climax, while exciting due to Selick's ability as a director, is contrived. Fantasy films are devilishly hard to do well; in an environment where anything can happen, rules are necessary to keep the story honest. This film is sorely lacking rules. It also lacks logic with regard to certain props.
The relationship between the film's real world and the film's fantasy world is confused. Some in the real world know something about the fantasy world yet others, who directly experience the fantasy world, know nothing. There is no explanation as to why some characters know more than others.
There are two competing strains within each animated film maker. There is the magician who seeks to dazzle the audience with beauty and artistic surprises and the dramatist intent on saying something about the human condition. In Selick, the magician has the upper hand.
Coraline has strong echoes of The Wizard of Oz and Spirited Away, and while it can compete with these films in the area of visual delight, it compares poorly in every other way. There is fantastic work in this film, but it's built on a weak dramatic foundation. With a stronger script, this film would have been an instant classic. Instead, it's just eye candy.