We know that Tom Hiddleston will be back as Loki in Thor: The Dark World, and judging by the trailer and what has been revealed of the plot, he'll play an even bigger role than before. But Loki's presence in an Avengers sequel has been less certain, and Whedon seems to have cleared it up once and for all on the Empire Podcast. When asked if we'll get to hear Loki spin another old school insult like "mewling quim", Whedon had this to say.....
Whedon: "Everyone is going to be looking for the Loki-Hulk smash moment [in Avengers 2] and you’ll be looking for quim. 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. Although I do think we should bring the word back. Not as an insult, it’s just a nice word."
With Thanos expected to make his terrible presence felt in the film, plus the introduction of morally dubious characters Quicksilver and Scarlet Witch, finding room to fit in Loki would have been a tall order. The Avengers 2 opens on May 1st 2015.