First off... if you didn't like the book, no one cares if you don't like the preview/movie. Go find your soul in some other story.
Meanwhile. For those who did love the book...
Here's some grand info - the author of Where the Wild Things Are, Maurice Sendak, worked closely with Spike Joneze on developing this movie and, in fact, gives a glowing seal of approval on this movie that is a creature all its own from the book.
Check it out in his own words:
Apple - Movie Trailers - Where the Wild Things Are (click on "exclusive featurette").
I am super excited for the movie. An hour+ is a long time to fill, but there's lots of subtext in that book that didn't need to be explicitly stated but is simply understood by all children. I imagine lots of this will be manifested in the movie and make great filler aka character & plot development.