10 Changes That Would Have Saved The Hobbit
6. Not Revealing Sauron As The Necromancer
Tying The Hobbit back to the original Lord of the Rings trilogy was bound to happen. It would be impossible for Jackson to not reference his movies in The Hobbit, especially given the prominent and recurring role of Gandalf and the discovery of the One Ring.
But Jackson overshot the mark. Rather than laying a few sinister hints to the Dark Lord and the wider story, Jackson plastered Sauron in at every opportunity. He went from getting a fleeting (and unnamed) mention in the book, to an entire action sequence that only served to distract from Bilbo's story.
Admittedly Jackson was faced with a conundrum. In Tolkien's book Gandalf disappears for a huge portion of the narrative, the explanation given, is that he had business dealing with the Necromancer - it's only in The Lord of the Rings that we find out this was Sauron. This works on paper, but Jackson couldn't do away with Ian McKellen for half the story.
But he should have had Gandalf do something that tied into the central story of The Hobbit, rather than alluding to the future plot in Lord of the Rings. Gandalf could have been shown discovering the orc army assembling to attack the Mountain; Jackson could have even alluded to Sauron's influences, building the idea of a looming but hidden threat. This would have been a far more effective way of handling the disappearance of Gandalf, without pulling the momentum away from the primary narrative.