Overall, I really enjoyed The Hobbit. I can, however, sympathise with many of its critics. For the Lord of the Rings films, Jackson (et al.) had to exclude parts of the story to fit it all into 3×3+ hour portions. For the adaptation of The Hobbit, a lot more material was brought in to stretch it to a second trilogy.
Cynically, one could assume that this was done for commercial reasons. From what I know of Peter Jackson though, I imagine the decision was made to make the most of what may be our last chance to see films set in the world of Middle Earth.
Aside from The Hobbit, the only other Tolkien book that could have provided suitable and sufficient material for additional footage, would have been The Simarilion. However, it seems that these rights are still held by the Tolkien family and they aren’t great fans of the movie franchise.
So, Jackson took The Hobbit and stretched it. Much of the extra material comes from the appendices of Lord of the Rings, so can reasonably considered “canon”.
In most cases, I think this works very well. Radgast the Wizard was a nice inclusion. He was mentioned in The Hobbit and was fleshed in the appendices. There were really only small embellishments to his part.
I have mixed feeling about the action sequences. While they continued the tone and feel of the Lord of the Rings movie trilogy, they were a far stretch from what we read in the book.
I have heard one explanation for how to reconcile these mismatches. A critic suggested that we remember that the in-world book “There and Back Again” (the fictional version of the real book, The Hobbit), was by Bilbo Baggins. The book, both in-world and real, was targeted at children. As a result, much of the action would have been toned down appropriately. In this context, The Hobbit movies can be considered as showing the story as it ‘really happened’.
This makes some of the differences between the book and the movie far more palatable. The extended Jackson-esque action sequences can be better understood from this point of view. No, they weren’t in the book, but perhaps the book self-censored them.
So while I won’t criticise the action sequences as deviations from the novel, they do reveal the biggest problem I had with the film. Many of The Hobbit characters are modified in ways that are off-putting. In the book, the dwarves were bumbling fools. In the film, they are portrayed as awesome warriors.
Ironically, this is the opposite of a grating change that Jackson included in the Lord of the Rings. Gimli of those books is a great dwarven fighter. The Two Towers movie turned him into comic relief and weakened his character unnecessarily.
The character change that I found most jarring, was Gandalf’s beefed-up role as deus ex machina. In a number of scenes he arrives just in time to save the day. For me, this ruined the climax of the one of the best scenes in the book, that with the trolls. The book has Bilbo show his value to the troop with his bravery and quick thinking. He uses his wits to distract the trolls long enough for sunrise to petrify them into statues. The movie robs Bilbo of this victory by having Gandalf turn up with unnecessary flair to a contrived solution of cracking a boulder to let the sunlight in. Further, this gives more foreshadowing of Gandalf’s power than was necessary.
The Hobbit could have been squeezed into a single, Jackson-length film. The original plan was for two films, which probably would have been the right number. We won’t know until 2014 as to whether the choice for three films was the correct one, but so far it looks like Jackson’s gamble may pay off in movie quality, not to mention financially.