It would make more sense if you were viewing on a 2.35:1 screen. The transition is supposed to open up to a wider panoramic view. They did it correctly for home video. Doing it the way you suggest would be like an IMAX opening that would shrink down to a smaller point of view. Other movies that...
Not that anybody cares about the DVD of Brother Bear that is included in this package, but it does not have the movie in it's OAR (as claimed on the packaging). It is a repressing of the Bonus Disc from the original DVD release and only contains the "family-friendly" modified aspect ratio of 1.66:1.