I was very pleased that the Thor that exists in the beginning of the first movie was not a fully developed hero, king, or warrior, he was young and arrogant. I liked that he didn't just start out as a 2 dimensional "hero" that didn't develop at all. The writers could have taken the Thor character from The Avengers and the Thor comic books who was already heroic and had most things figured out. I was impressed to see a lot of the family dynamics between Odin, Frigga, Thor, and Loki coming mostly from the Norse myths than the comic books.
Thor's relationship with Loki was very interesting in the first film. Thor really cared for his younger brother but still believed that he was smarter and more worthy than him (in more than the regular "sibling" kind of way). Loki from the comic books and the Norse myths was a liar and a maker of mischief so basically he made life difficult for everyone in Asgard just for some laughs. All back story on Loki aside, this puts him at a disadvantage in the running for king to begin with. Loki has made it difficult for people to trust him and I think this makes Thor feel superior to Loki. In the film we hear some lines from Thor like, "know your place, brother" in response to Loki giving Thor actual wise advice. Heimdall and Odin are also not interested in anything Loki has to say, ever. But during Thor's time on Midgard (Earth), he changes when he realizes that his father has told him he is unworthy of the throne because of his arrogance. When Thor is stripped of his powers and falls for a mortal woman, he learns what it is like to not be able to resolve every problem by going to war, and he learns what it feels like to want to help and protect someone. Once he becomes "worthy" and returns to Asgard, it is hard to say whether he still doesn't trust Loki, but he definitely cares for him and he may have regretted the way he treated him in the past but he doesn't mention it or apologize. I just really liked how they both started out as somewhat naive young men and we were given reasons on how they developed into their iconic characters.
Now: Loki's transition from "Thor" Loki:
Then there's the end of the credits scene where we see Loki starting to control Eric Selvig's mind. It's hard to say how long Loki's been on Midgard and how fast he thought of a plan or if it was in his mind the whole time, but Loki seems to now be searching for power. This is completely understandable since I think there's only so much hatred a person can deal with before their heart stops being sad and starts to become ice cold.
So Loki's transition is so psychologically understandable, he goes from crying for 50% of the Thor film to demanding some respect. He's gone beyond trying to win the approval of his family to giving up completely and takes it into his own hands to try and become king. This part is very interesting to me since Loki has somewhat abandoned Asgard yet still introduces himself as "Loki of Asgard". He knows of his Jotun heritage- which means his skin is naturally blue and his eyes are naturally red- but he still chooses to walk around with an "Asgardian" appearance (caucasian skin and blue/green eyes). This shows us of the shame that Loki still believes to come with being a Jotun but he doesn't refer to himself as Thor's brother or Odin's son as he says to Thor that he is not his brother and asks if Thor knows of his true parentage. I thought it was quite sad that Loki also asks Thor if he mourned while thinking he was dead. As if he thought that his family wouldn't even mourn his death.
In Thor 2, I'd like to see Loki have some sort of reconciliation with Odin, Frigga, and Thor even though this has never really been done before. Even though I think that Loki will continue to be a menace in the second Thor film, I'd love to see something resolved between he and his family. My prediction for what Loki's situation will be in Asgard, is that he may be yelled at and imprisoned like how he often is in the myths and comic books, and he will somehow get out and continue to be hated while more distance grows between he and his family.