Now, I have no proof that the above is what's happening, but it's the only thing that explains why Thor is such a "meh" experience. Thor doesn't feel like a movie so much as a sort of biography, explaining the character and creating context but not a real story. And given the behind-the-scenes talent, that is really really sad.
Basically, we are dealing with Silver Age Thor here. Thor (Chris Hemsworth) is the son of Odin (Anthony Hopkins), the all mighty god, and loves his brother Loki. Thor is very much a warrior and enjoys nothing more than a good scrap. One day, longtime enemies the Frost Giants break into Asgard and nearly abscond with some MacGuffin Odin took from them during their last ancient battle. Thor leads a small team to confront the Frost Giants against his father's wishes. For this, he is stripped of his powers and banished to Earth to learn humility. Which he does in roughly two days. (I know, but this is a god, not an ordinary dude. He's supposed to do things humans can't.) Meanwhile, Loki is revealed to be working on plots, although the ultimate goal not only is not revealed until the end, not only is it kind of weak for his character, but kind of like how bad ass Darth Vader was pussified by losing his mommy and his wife, Loki's motivation makes him seem like less of a manipulative sinister being and more like a child more petulant than Thor was.
The big story is the director, Kenneth Branaugh. He directs Shakespeare, ya know! And a lot of critics breathlessly talk about how Thor and Loki's relations to their father smacks of King Lear. These critics should be humored and pitied. I've read King Lear, on my own without having an English teacher make it mandatory (still read Shakespeare once in a while, in fact), and the intercharacter relations are nothing like Lear. The key to Shakespeare is not that you understand Shakespeare, but Shakespeare understands you. The character motivations, doubts, fears, hopes, everything, have analogs in the everyday lives of normal people. And most normal people would at least be suspicious of Loki's motivations far earlier in the film than they do, especially Odin. There is no true fatherly angle presented here, just Thor did something stupid and Odin wants to teach him a lesson. When Frigga (Rene Russo, COMPLETELY wasted in her role) tells Loki that Odin doesn't do anything without a reason, you get a glimmer of hope that maybe Odin had some sort of "just in case" plan in place and Loki should be worried that he overlooked something. Instead, it just triggers an action sequence with a 'roid case suit of armor called the Destroyer.
Branaugh gets very little to work with given that a story credit goes to J. Michael Straczynski, a Lord Of The Rings nut who also gave us the sci-fi classic Babylon 5. In fact, the battles with the Frost Giants evoke quite a few memories of orc battles. JMS is a great writer. Even when stuck with things that were potentially dopey (Captain Power And The Soldiers Of The Future), he still writes solid stuff that survives logical scrutiny and makes the characters seem like actual people instead of just plot devices. This is ultimately where Thor goes wrong. The story basically gives us an action-packed opening and an action packed third act, but a slow middle that doesn't feel right. Nothing really interesting happens here, especially given that Thor works best as an action hero (duh, it's his shtick). A movie that should have been angled more like last year's Star Trek movie (that Hemsworth had a bit part in), combining its action with the political intrigue of classic B5, could have been served up. No. Thor operates more like Jim Groat's Pretend Beer God than the God Of Thunder. You sit there and wonder why Loki's plot is taking so long to unfold. Given he is the only character using his brain for something other than keeping his head from caving in, he probably could have taken over half of the known realms before the second reel. While there is some good dialog and a couple of nice character moments, JMS blows it. The fish out of water comedy has been done before. And when he does an It's In The Script moment, where characters do something in defiance of all logic just for the sake of the plot (why oh why didn't the Frost Giants kill Heimdall, and why did he survive when the Warriors Three were at risk of death from being frozen?), JMS is stumbling bad.
Production values are fine. Natalie Portman does fine given the limp material, although her love with Thor is actually believable, unlike her love for Anakin in that other franchise. Hemsworth actually does fine in the role of Thor. There's a fan service moment for the ladies, and he gives Thor a cocky swagger, making him seem supremely confident without being a dick about it. At the end of the movie, he gives Thor a weariness and humility that makes you think he's playing a completely different character. Loki is fine, a manipulator who thankfully stays away from "twirling his mustache" territory. Set designs for Asgard are appropriately ornate, although it took me a minute to figure out that the disco light bridge in the movie was supposed to be the Rainbow Bridge. The action sequences, unfortunately, aren't all that spectacular. I mean, yeah, they're impressive, but you expect more from a movie about gods. Special effects are now only limited by the imaginations of the SFX crew. And if they aren't that imaginative to begin with, well....
The music score by Patrick Doyle is perfunctory, but not noteworthy. The scene where
Side note: if you are given a choice between 2D and 3D to see this movie, see it flat. The scenes with the Rainbow Bridge are the first time I've watched 3D effects and actually started feeling queasy.
All in all, Thor is 130 minutes of backstory that you could just read on Wikipedia without spending $13. It's all set-up for another movie, not a movie in it's own right. Not bad, but if you have better ways to spend your time, do it.