Caught Thor tonight and it pleasingly exceeded my (admittedly not sky high) expectations. When Branagh talked about it being a character driven movie, he did put his money where his mouth was and even minor characters were given time to develop.
I was concerned that The Warriors Three and Sif, for example, would be reduced to background characters, but those fears were ill-founded. And Loki's a rat bastard, but a rat bastard with actual depth and genuine motivation (although, with Loki, doing it for shits and giggles would have been perfectly acceptable anyway) with Tom Hiddleston showing remarkable restraint in the moustache-twirling department.
There's weak points - The designs lean more towards Star Wars than Middle Earth, but it's possible to see the reasoning behind it. Hopkins' Odin doesn't have the raw power and gravitas that Brian Blessed would have brought to the role (and still unsure why he was never cast - he certainly seemed to think he had been. Studio insistence of getting a big name actor, perhaps?) and Natalie Portman sadly lacks any real conviction or personality, but other bit parters like Kat Dennings more than make up for the shortfalls.
And then there's Chris Hemsworth, who's marvelous as the titular character, veering from raw passion to awkward charm (I wish they'd made more of the latter, in fact.) He's a definite keeper.
At the end of the day, any fears that Branagh couldn't do an action movie are ill-founded. He succeeds because he makes the story about the characters with the action being incidental, rather than vice versa. A refreshing change from many Hollywood blockbusters.