Thorin kills Azog, Bolg swears his revenge and chases Thorin. How hard is that?
Not in the least bit.
Boyens: "Well in our movie, Azog is the principal villain. The only problem is, chronologically speaking, he is dead by the time the dwarves set out on their quest. How do we fix that? Throw canon out the window and just keep him alive."
Fan: "But isn't there already an Orc commander during the time of The Hobbit? Bolg? He's Azog's son isn't he?"
Boyens: "Well yes, but we need Bolg to take up the fruitless chase while Azog gathers Sauron's forces for battle."
Fan: "This is about the hobbit, right?"
Boyens: "Well, Tolkien had started a revised, better version of The Hobbit that brought it closer to Lord of the Rings, but he abandoned it for some reason."
Fan: "Because The Hobbit was losing its identity."
Boyens: "Who can remember? Anyway, we are more interested in exploring the bigger picture of what's happening in Middle-earth rather than simply adapting The Hobbit. Finishing what Tolkien started, basically."
Fan: "Started, and chose not to finish."
Boyens: "Who can say?"
Fan: "It sounds to me that you're not so much interested in The Hobbit as you are in the overall Middle-earth mythos as they pertain to The Lord of the Rings."
Boyens: "The bigger picture is always better for three movies."
Fan: "Three movies?"
Boyens: "Well there is so much material with Inspector Gandalf and dwelf romances and Lake-town politics that we felt two films weren't sufficient. It's three films now."
Fan: "So why is this called The Hobbit exactly? It seems like nothing more than a footnote here. Everything happening as mere mechanisms moving the 'bigger picture.' It seems you are doing everything in your power to make it anything BUT The Hobbit."
Boyens: "It's in the spirit of Tolkien."
Fan: "Sounds like you guys weren't the best fit for this adaptation. You clearly have no faith in the story based on its own merits. In your minds, The Hobbit is only interesting if you stuff in all these Lord of the Rings tie-ins that do nothing but make Bilbo's story look inconsequential by comparison. How is it 'in the spirit of Tolkien' to break canon and willfully lose sight of the narrative being adapted?"
Boyens: "You'll find out in the extended edition."