I go to the movies very seldom. In fact, the last time was when I saw the first Hobbit movie (three-star review here). I'm unlikely to go for the third movie in the trilogy.
I had heard mixed reviews of Desolation of Smaug, and I tried to go in with low expectations to enjoy it as what it is: not as an adaptation of a beloved book but as a Hollywood blockbuster, with all that implies. I surprised myself by liking most of the story additions, even the love triangle with the OC Tauriel. (Let's face it, these movies are high-budget fanfiction.) What I didn't like was what I didn't like the first time: the de-rogueification of Bilbo and the utterly absurd action sequences. In both cases, this movie had more of them than the first one did, so there was more for me to dislike.
Bilbo first. Bilbo is one of the sources of the D&D "rogue" or "thief" character class, along with the Grey Mouser and a few others. Although he's still referred to as a "burglar" here, everything that makes him a rogue or trickster has been taken away from him. He didn't get the trolls arguing with each other in the first movie, and in this one he doesn't fool the spiders, he just fights them. He doesn't hang out in the elvish stronghold thieving and learning his way around, he just happens across the opportunity to get the dwarves out. The wine barrels are retained, though he doesn't pack the dwarves in them (so that there can be gratuitous and rather dull action sequences, of which more later). His bantering with Smaug isn't the (over)confident cleverness of a proven trickster - because all opportunity for him to become one has been removed; he hasn't gained any XP in Rogue. It's the desperate improvisation of a trapped incompetent who's out of his depth.
I neither know nor care whether Hollywood thickheads nixed the tricksterism on some vague moral grounds. All I know is that the essence of Bilbo's character has been lost.
So, to the action sequences. Here's a piece of advice Peter Jackson needs to heed. "Don't write action sequences. Write suspense sequences that require action to resolve."
There's no suspense about whether the dwarves will be killed by the orcs, or whether Legolas will be (since it's a prequel to movies in which Legolas is very much alive). There's nothing else at stake in the action sequences apart from who wins, and since we know that going in, they're boring. And they go on far too long. As a friend of mine commented, they would, ironically, be more exciting if they were shorter.
Not only that, but they're cartoonish and utterly, completely ridiculous. I compared the falling-platform-in-the-goblin-mines sequence in the first film to Michael Bay. The action sequences in this film make Michael Bay look like a sophisticated and nuanced filmmaker with a deep reverence for the laws of physics and human(oid) biology. When the youngest child in the theatre laughs out loud at how absurd a piece of action is, you've obviously missed your mark.
Legolas the superhero surfing down the stairs on the shield, swinging himself one-handed onto the horse or swarming up the mumakil were among the scenes I liked least in the original LOTR trilogy. Here, we see mainly Legolas, but also Thorin, performing the same kind of absurd feats. We see a great deal of fire (and even molten metal) that isn't, apparently, hot, based on its lack of effect on the dwarves. We see lots of action, but speaking for myself, I felt no tension whatsoever throughout the entire movie. The characters have character armour a foot thick, and timing that you'd never dare require in a video game because it would be unplayable.
I said of the first film that it was a long three-star movie with a much shorter four-star movie trapped inside it. This one is a long two-star movie with a much shorter three-star movie well-hidden underneath all of the nonsensical action.