Wes makes an interesting conjecture about why 3D animated movies tend to be better than their 2D brethren.  He speculates that the digital design of the 3D movie provides an increased capacity for iterative design; that is, when they realize something is wrong with their film during production, it is much easier to fix and modify the 3D digital scene than it is to toss out drawn cells and redo a 2D scene.  This paragraph from Wes’ blog is suggestive:

“One representative from Pixar claimed that the success of all the Pixar films resulted from having a good story. He added that, for each movie produced by Pixar, each one had been ‘the worst movie of all time’ before further editing.”