To be completely honest, I originally had issues with how this story--taken as a whole--was structured. And while I fully recognize that I'm just about the only person on the planet who had any problems with it, I still feel that what was there was creating some kind of confusion in the message that was being communicated. This is in contrast to the past fifteen years of Pixar films that I felt were more concrete in their execution of complete storytelling.
While it is clear that Woody was the principal character that changed, it is less obvious which character was the impetus for that transformation. At first glance, it seems as if it is supposed to be Andy as the most emotional scenes involve the college freshman-to-be and his cowboy toy. But Andy's realization that the time has come to say goodbye comes off more as the last predictable event in a series of well-intentioned setups and payoffs, rather than a point of emotional growth developed naturally over the course of the story. Andy’s resolve (what to do or not to do in regards to Woody) was what the film set out to be, but for some reason was relegated to a teary-eyed bookend device.
The Andy/Woody story (with Woody remaining the "steadfast" toy and Andy changing) appears to be the concluding emotional event to all three films, rather than the singular end of this particular film. This was the source of my confusion in my original analysis. Seen in the context of all three films, Woody is Steadfast, and Andy is Change. Taking this film as a singular piece, Woody is a Change Main Character. The conflicting contexts proved to be the reason for the inaccuracy in my original analysis.
The second, less obvious choice for their counterpoint to Woody's point-of-view, would be the Toy Family (Mr. and Mrs. Potato Head, Hamm, Buzz, etc.) Here the argument about "being there for Andy" vs. "being there for other kids" seems to fall into place and perhaps suggest what the story is truly about. The only problem with this is that the argument is not fully explored, leaving more time for throw-away gags (Ken) and classic film references (the phone) than emotional growth.
The most atrocious affront to meaningful story structure, however, lies in the literal "hand of God" that descends to save our heroes from an almost certain death. Conveniently setup, this solution to the story's major problem came at a most unusual time emotionally; a surprise that, while welcome, had no real significance to the story's message. In this respect, Toy Story 3 shares shelf space with the pantheon of Spielberg final acts that end because they are supposed to (see Saving Private Ryan or War of the Worlds or Jurassic Park), not because they meaningfully developed to that penultimate moment.
That being said, the overall entertainment value of the piece well supersedes any errors with how the story was constructed. Ken is a welcome addition to the already wonderfully imaginative characters as is Buzz's new found dancing skills. And there is some character animation--particularly on the part of the little girl, Bonnie--that is so truthful it surpasses most, if not all of the performance capture found in Avatar.
In addition, one of the five stars above was solely earned by the Teddy Newton-directed short that appears before the film. A great concept and some spectacular character animation make this adventure to the theaters this summer more than worth the 3D premium charge.