Joss Whedon has confirmed that The Avengers 2 will not see Loki fully rehabilitated and ready to party with all his new best friends. Loki won't be in there at all, in fact. Speaking to Empire, the writer-director explained that he fears the inclusion of Loki would just have everyone waiting for the character to finally spout his hilarious catchphrase, saying:
"Everyone is going to be looking for the Loki-Hulk smash moment and you'll be looking for [a "mewling quim" moment]. First of all, imitating what I did before is the surest way to do it not as well. Second of all, Loki's not there to say those terrible things."
You're right about that, Whedon. But since it increasingly seems the reason Loki is there is to sit around in a transparent prison cell, maybe he could still come back for some gritty, Oz-style intros?