I think I need you to explain "Save the cat" again RC, because you use it like Fezzini used inconceivable in the Princess Bride.
My understanding is that STC is a method of storytelling, much in the way Campbell's Hero's Journey has been applied to movies. In STC, though, it's a simplification of the narrative and the characters designed to lead the audience along in a sort of paint-by-numbers approach to narrative, right? It ultimately boils down into a "tell" vs. "show" thing. The story moves along because the characters are forced to make decisions that the audience understands and would make for them, and suspense, etc, is artificially applied to the story through trope-like classic methods (Ripley saves the cat/Newt/her immortal soul, "the call is coming from inside the house," etc.)
Am I sort of on target there?
So in the Hobbit movies, Jackson is doing what the Tolkien estate -- namely Christopher -- has been trying to do all along. He combined the posthumous collections into the larger story. The Tolkien estate has been making hay off of JRR's notes and story bible that was written largely to help him create the universe and then discarded. Some of this stuff ended up in the copious appendices in all the books, but the rest went into the bin until Chris Tolkien went on the cash-in train.
If anything, The Hobbit trilogy is so suspiciously toeing the line of the Tolkien estate's wishes for how the source material should be told, it feels like the Hobbit trilogy is some sort of payoff for being allowed to do LoTR somewhat loyally...
But, in terms of strict storytelling, Jackson isn't taking the sort of liberties that STC would imply. He's staying with the source material, it's just a question as to whether or not he should be using the source material that he's using. If you take the Silmarillion and the Red Book stuff and all the appendices and The Road Goes Ever On and Unfinished Tales and Lost Tales and The History of Middle Earth (a twelve book series largely devoted to JRR's notes about the background motivation of characters in LoTR) and the Miscellany and The Children of Hurin and assume that they're all part of the larger prologue in which The Hobbit is merely a chapter (as Christopher Tolkien would love for you to do) then, viola, you have a trilogy from a children's book you can read in a couple hours.