Thor 2 - The Dark World (Potential Spoilers)

As there is Captain America 2 and Iron Man 3 threads why not have one for Thor.

So Thor 2 will see Thor and Jane Foster travel to other worlds in the 9 realms, i've seen a few ideas of what could be happening in the film.

First is that the film will feature the dark elves, with Loki trying to get hold of a weapon that only frost giants can use, don't remember its name.

A theory i've read is that what if Loki's plan all along in The Avengers was to be captured so that he could return to Asgard to help Thanos steal the infinity gauntlett? What better person to help him acquire it than an asgardian?

My personal choice of what I would like to see would be the return of the Red Skull, people may say its too soon however he was transported to a different realm there could be a good chance Thor would run into him. Maybe that would be a plan for Thor 3 instead to try and make us forget about him a bit.