10 Worst Changes Peter Jackson Made To The Hobbit
5. Having Too Many Antagonists
In Tolkien's original story, Azog was not the main antagonist. In fact he didn't even make an appearance. In the book, the dwarves manage to stir up the goblins of Misty Mountains, after they slay the Great Goblin King. At the end of the story, the goblins reappear, led by an ancient enemy, Bolg son of Azog. Their motivation is one part greed - after hearing about the death of Smaug - but also revenge for the death of their king.
Jackson was right to flesh this out for his movies. It was important that we had some sense, that the goblins and orcs were plotting away, rather than just appearing out of nowhere at the end of the third film.
But the movies suffered from having far too many villains being presented as the main antagonist. Firstly, we had Smaug - the reason for the entire quest of Thorin and co. Then, Azog gets thrown into the mix, along with Bolg, who's only purpose is to give Legolas someone to fight. On top of that, Sauron gets plastered in at every opportunity, just in case we forgot about his presence in Middle-earth.
Smaug was essentially pushed to the side to focus on Sauron, and Bolg and Azog just wrestled for screen time, with their only real motivation being that they are evil.