No . . . I'm really asking-- "Could he?" Because though I consider myself a huge Idris Elba fan, I'm sorry to say that I have yet to watch the first Thor, so I don't know if Heimdall made it out in one piece. And characters-of-color don't typically fare well in action/fantasy films when they're not the lead character.
Anyway, Thor 2 is indeed coming. And if Elba is attached to the sequel, he's already faring better than director Patty Jenkins, who was recently relieved of her duties by Marvel due to creative differences, according to THR. Had Jenkins stayed on, she would have been the "first female director of a Marvel movie and only woman to ever direct a big-budget superhero or comic book movie."
I guess no minority group is safe when it come to these types of films-- in front of or behind the camera.
Thor 2 is slated for a Nov. 15, 2013 release.