Originally Posted by Keyser Soze
It's not just the fangirls who think Loki should have a redemptive arc. I think it's a natural, sensible place for the character to go, given his portrayal in the last two movies, and especially with a new villain taking centre stage in this film.
Taking this approach is not just fan-service, and it's not untrue to the character. Some of the best Loki stories in the comics have dealt with his moral ambiguity and tackled the question of whether or not he's beyond redemption. Just making him an evil badass would be a step backwards at this stage, and would be doing a disservice to the complex, conflicted character Tom Hiddleston has so skillfully brought to life.
Now obviously I don't know what it would be like, but if this did end up happening, I would be totally disappointed. I like fully evil Loki. He is a screwed up, unstable being with an enormous ego and no empathy. He has already tried to destroy one planet and force another into subjugation, after getting in deep with some space gangs. I wouldn't want to see that guy all of a sudden turn good after everything he has done, it would seem (to me) out of character, based solely on what has happened in Thor and The Avengers. If anything I think he would be bitter than he lost and only drive him to do something on a larger scale.
I especially loved Whedon's take on Loki, who he wrote as a purposefully over-the-top evil, theatrical villain. I felt like it was kind of an homage to old school villains who were very theatrical in how evil they were. This is the guy who snickered at the sight of sentiment...how much more exaggerated evil can you get, lol? I thought it was awesome. This character doesn't have any moral ambiguity. He is evil, and I like it that way.
If he does do something indicating he has had a change of heart, I only hope it is part of a larger villainous plan in which he is just doing it to trick Thor, or Odin or whomever.