And I'm not saying that just because they deviated from the book. I was quite okay with their decision to deviate from and expand the book's story, the White Council taking on the Necromancer and all that. Nor did I have a problem with them making up that new character Tauriel (although I did have some reservations when hearing Evangeline Lilly's descriptions of her character's supposedly well-developed background - entirely justified ones, as it turns out).
But when watching the actual movie - seriously, is that the best the scenarists could do? How are Boyens and Walsh, who did an imperfect but reasonably good job in the LotR trilogy, so bad in this one? Evangeline Lilly is convincing enough as an actress, but the scenarists gave her character a distinctly un-Elven personality and zero background or character development, beyond her semi-crush on Kili and her funny faces while Thranduil discussed the possibility of a relationship between Legolas and herself in about ten seconds flat. The Dol Guldur storyline can barely even be called a storyline by any definition of the word, and certainly not coherent - Gandalf nearly gets himself killed, twice, heading for some impossible inaccessible location to do, what, exactly? Meet up with Radagast so he can send him off later as a messenger to Galadriel? Can we at least try to make some sense? If you're going to have a White Council storyline, then how about you actually involve the White Council. Where is Galadriel (other than her tiny telephatic contribution), and where is Saruman? They'll be there in the third movie, no doubt, but they should have been in this one. And then you've got all the very remotely believable (the Laketown scenes) or completely absurd (the barrel section, the dwarves vs. Smaug stuff) action scenes that fill most of the movie.
The LotR trilogy has a number of strengths (the music, basically everything visual from make-up and costuming to props and landscapes, decent to good acting from everyone who matters) and the one big weakness in the scenarios. I wasn't really expecting the Hobbit to do any better on that last point, what with them having to make up stuff on their own to add to Tolkien's story, but I didn't expect them to be this atrocious either - and while the music and visuals are mostly up to the old standards (mostly - what's up with that horrid song over the end credits?), that's not new or particularly captivating anymore now.
I don't mean to sound entirely negative - I did for the most part enjoy watching the movie, and there were certainly good moments, including as a definite high point the Bilbo-Smaug conversation (after that I wasn't too impressed by Smaug's stunts or conversation). No complaints about the acting, either, Richard Armitage deserves a mention for his very good job with Thorin's quite complex character. But seriously, there were far, far too few good things about this movie that didn't come from either Howard Shore or Weta, and those two are things that the fans already take for granted. We expect more than that. I don't know how you can recruit Benedict Cumberbatch and Stephen Fry for your movie, while already having Shore's music and Weta's great work and decent to good actors in all recurring roles, and still not produce anything better than this.