Wha . . . 
The Hobbit a darker book? Heavens no! It's a childrens book; it's infinitely lighter and more pleasant than the despair and seriousness which fills so much of his other works. The movie needs to reflect that.
With the risk of going on a rant that is totally off topic - I have to disagree!
Yes The Hobbit is dressed up as a children's tale but the dark side of the novel cannot be ignored.
Gandalf tricks Bilbo into undertaking a perilous journey - Bilbo & the company are attacked by various creatures e.g. trolls, wargs, goblins, giant spiders (same as LOTR), after becoming lost deep underground he meets Gollum and ends up with the ring (thus risking a similar dark influence as Frodo), the Silvan elves of Mirkwood then threaten the lives of the dwarves, blah, blah, blah... and of course we can't forget the star of the show - Smaug who doesn't really sound like the cute, fluffy bunny type.
Zohar Shavit wrote an interesting criticism of The Hobbit titled 'The Ambivalent Status of Texts: The Case of Children's Literature' in which he insightfully explained the following:
"The ambivalent text is deliberatley aimed toward two different groups of readers: children and adults... As the norm of complexity and sophistication is prevalent for some literary periods in the canonized system for adults, those adults who belong to the elite's consumers of the latter system are more likely to realize the sophisticated text in full, while children, who are used to the reduced and simplified models, are only aware of the well recognized established models. Thus, the less sophisticated child readers totally ignore several layers of the text."
(The readiness of an inferior system to accept the well established models only, is characteristic not only of other systems in the literary polysystem, but also of other semiotic systems, especially of social systems).
Although I should stop ranting otherwise I'll start quoting from my uni dissertation on The Hobbit! I just think it's important to recognize the conscious artistry of Tolkien and how he directed different parts of The Hobbit towards the different age groups of his readers.
Too excessive?
