The main problem is that when Tolkien wrote hobbit, it was just a plain fairy tale. In a fairy tale, there is no centuries-spanning background for the characters, no uberscheme of eternal good fighting eternal evil.
The trolls are not twisted servants of Darkness, attracted by the whispering of the One Ring, but just a bunch of stupid monsters that crave human flesh, and that turn into stone when touched by sunlight - and that's that, end of scene, cheap little thrill, and let's move on. Gandalf is not an incarnation of a demigod, but rather an old-fashioned wizard with a few spells under the hat, an aging fellow who enjoys a good laugh. And when he is done providing hints and help during the tutorial, he "suddenly remembers he has something important to do elsewhere", because the author has realized he is stealing all the EXP and robbing the story of the sense of danger ("Gendolf will save us, right?"). And the ring is just a magical trinket, like the purse of eternal gold, or a horse that can speak - they are found in every old fashioned fairy tale.
The whole X-files style epos of the struggle of good versus evil with complete mythology including gods, demons and history spanning thousands of years was written later, to seamlessly wrap around the simple tale the Hobbit originally was.
The problem with Jackson's (and every Tolkien nerd) approach is that by constantly showing "look, this simple detail have far reaching context, and I am clever enough to know it", and inserting those references into the story, you are destroying what the Hobbit originally was - a simple tale for children, similar to those of Grimm brothers.