There are so many ways that they could have gone with the story. For instance, had this been a foreign film I am sure we'd have the story from Casper's POV.
So, instead we get an audience POV from the Kat character to make it more mainstream. The film is very uneven but what can you expect from a movie based on a cartoon ghost?
The film does have a charm to it that works if you allow it to. The gags are numerous but they mostly miss their intended target. The actors are fairly entertaining when they need to be such as Bill Pullman and Christina Ricci. The visual effects are quite decent but they toon-looking ghosts and the human reality makes it a strange spectacle.
I think the film would have worked had the Carrigan story been excised and it was just a father and daughter encountering a haunted house with spirits.