I haven't seen the Hobbit yet, but I disagree with Tolkien's son. The films of the Lord of the Rings were completely appropriate, as those novels are basically the telling of a war along with a hero's quest. Those are both very appropriate for an "action" type movie.
However, I can see his criticism of the Hobbit being valid, as the hobbit is more of a coming-of-age/quest novel. I think that Jackson is trying to transform the source material into more of an action/war movie in the same vein as LOTR, and I can see that causing problems and contradicting the "feel" of the novel.
In this world of sin and sorrow there is always something to be thankful for; as for me, I rejoice that I am not a Republican.
- H. L. Mencken