Tolkien’s Bilbo is no warrior, and he never becomes one. He earns the dwarves’ respect in more subtle ways. Jackson’s Bilbo, on the other hand, has a rather berserker-like moment, gaining him the admiration of Thorin. Ironically, the screenwriters, not Tolkien, are the ones who put these words in Gandalf’s mouth:
There are some other problems, like the over-the-top video-game-like fight sequences in the goblin tunnels, and the anti-climatic demise of the Great Goblin. The screenwriters seem to be attempting to combine both the darkness of "The Lord of the Rings" and the whimsy of "The Hobbit." Jackson did a great job in "The Lord of the Rings" providing comic relief while telling a dark story. But his attempt at whimsy this time around sometimes comes off as childish rather then whimsical.
However, one whimsical sequence that did work rather well was the Trolls. Some fans have complained a bit about the crude bathroom humor, but after all, they are Trolls! The scene does find a balance between tension and comic relief, and gives Bilbo a chance to show his quick wit, even if it was Gandalf’s wit that saved the day in the book.