Together with Daniel James and Heiko Reinemuth I have been able to do some analysis regarding the dialog of the Hobbit: the Desolation of Smaug. I did a similar thing with an Unexpected Journey last year and discovered that Bilbo and Gandalf spoke the most by far. Since the Desolation of Smaug is more geared towards action I was interested to see what the result would be.
As you can see, the Desolation of Smaug has far less dialog than An Unexpected Journey (6237 and 9132 words respectively) and it is also more spread out. The cause for this is probably in part the lengthy action sequences and lack of monologue in the beginning. You can see the distribution of An Unexpected Journey here.
One positive change for Bombur is that he does say something in the new Hobbit movie, even if it is only one word (“Alright”).
The data for this analysis has been put together by the Google+ page The Hobbit Movies of which I am one of the admins. It should not be considered absolutely accurate but rather a good estimate of the dialog.