"In a way, it becomes more difficult at this point," he told Empire (as quoted by Comic Book Movie). "Thor 1 was the origin story and he starts off as a brash child and ends as the hero; the danger then is, where does he go from here? If he doesn't change, he's gonna become boring. How do you break him down again to rebuild him and have some sort of arc, some sort of journey? Avengers was different, it was the arc of the team. So now, on [Thor: The Dark World], we've been really throwing around, 'Okay, so what's Thor's big conflict here?' Because it can't just be that bad tempter again, or that he's too cocky. We've done that. And now, where does the humour lie? Because it can't be the fish-out-of-water, Crocodile Dundee kind of thing that we had in the first one. He's been to Earth now."
It's an insightful quote, and there are at least two or three observations there that are key to making the sequels work and making them interesting.
There's apparently a new sensibility coming into this film a bit as well, which makes sense given the fact that we've been told so much of it will happen in the other realms. But it seems as though incoming director Alan Taylor plans to focus more on the mythological and the fantastical than the somewhat more grounded, science-fiction approach to the Norse gods taken in Kenneth Branagh's first film.
Said Hemsworth of Taylor's approach, "If you look at Game Of Thrones, what I love about it is that it has that mythical element but you're always grounded in such an organic world. I think that's the goal scored second time round."