I just came back from The Desolation of Smaug – well, about an hour ago as I type this – and I just have to say here that I thought it was epic. I thought the first one was pleasant enough, but I enjoyed this one throughout, not the least of which for those little moments of wonder that got to play out briefly, here and there – and at the end, in broad swipes of amazement.
You see, they desperately, desperately needed to sell Smaug in a way that Smaug has never been sold to me, even in the novel. Smaug needed to be convincing, and terrifying, and he was, and it was beautiful.
Also, I found Tauriel to be a great addition and am thinking about my cosplay options; haters may step off right now. She’s complicated and interesting and yeah, frankly, representation matters, and I’m glad we didn’t have to go through seven hours of fantasy film without one woman.
There’s all sorts of added stuff, not just Tauriel. Mostly – not entirely, but mostly – I found these to be positives. We finally get some motivation for all the combatants in the War of the Five Armies; the dwarves have motivations of people, rather than caricatures; all these character additions are making that whole fight make a lot more sense from a motivation standpoint.
As for these purists out there who whine, “It’s not like the book!” in one variation or another? All I can say is no shit, purists. For one thing, I am going to remind you: Bilbo is an unreliable narrator in canon. He changed his own retelling. Like between the first and second editions of the novel, The Hobbit, where he went from “finding the ring lying about” to “that whole thing with Gollum.”
Kind of important, isn’t that? Wouldn’t really leave that out, would you? That’s the definition of an unreliable narrator. So, knowing that, how much else did he not bother to mention? It is reasonable to guess quite a bit.
There and Back Again is Bilbo telling his version for his people that makes him the total hero of everything. Also, it’s kind of the version for kids. That’s going to leave a lot of bits out. Adding other bits back in – particularly from the appendices – tells more of the story, not less, and doesn’t “get it wrong;” it tells another person’s version of it.
Which gets to my real point:
Tolkein explicitly and specifically wanted this to be a broad, wide-reaching English-language mythos, like the ones the Germanic peoples have. A defining element of myth is that it gets told and retold and changed and reinterpreted and fit to what people need and want when it’s being retold. That’s the whole point of a mythos. Going on about “changing it is wrong!!” is missing the entire point of Mr. Tolkien’s actual stated endeavour.
That’s not an argument for liking this retelling, if you don’t like it. There’s plenty not to like, depending upon your tastes. Yes, the film’s pacing is a little weird (but no less weird than the book), yes, some parallels are a bit too heavy-handed. That’s all fine.
But that it’s added to – and in some cases changed from – the book; that’s not “disrespecting the material.” Not in this case. In this case, it’s the exact opposite. It’s proof of Mr. Tolkien achieving his goal. It’s one of those cases where reinterpretation isn’t just okay; it’s a tribute.
eta: Anna has a long review post, here.
Over the last couple of days, 
