it could be as simple as a reference to him like Erik referenced Banner in Thor 1.
another idea that occurred to me, if Strange were in it, if they do Dr. Strange film in a 2016 (still 3 years away), then that is likely to be a creation/how he got to be this way, story (also what the IMDB listing currently says), and so he is unlikely to appear as the Sorcerer Supreme of Earth in Thor 2 anyway....he's just going to be a normal human. But from his bio I've read about him, before he was Sorcerer Supreme, he was a doctor that was in a car accident that damaged his hands so he could not longer perform surgery.
SO what if, his appearance in Thor 2 is that he is a surgeon in London during the Dark Elves attack and he is injured then? Maybe even witness to Malekith using magic and becomes interested in the mystic arts as a result of that, perhaps as a way to try to cure his injury? that would set him up well for the movie a few years down the road if he's been dealing with this injury for a while. And it would not take too much away from Thor being a Thor movie, as I fear some of your other suggestions would, while at the same time giving a very useful lead in to the Dr. Strange movie. It would only be a scene or two cameo thing.
another idea that occurred to me, if Strange were in it, if they do Dr. Strange film in a 2016 (still 3 years away), then that is likely to be a creation/how he got to be this way, story (also what the IMDB listing currently says), and so he is unlikely to appear as the Sorcerer Supreme of Earth in Thor 2 anyway....he's just going to be a normal human. But from his bio I've read about him, before he was Sorcerer Supreme, he was a doctor that was in a car accident that damaged his hands so he could not longer perform surgery.
SO what if, his appearance in Thor 2 is that he is a surgeon in London during the Dark Elves attack and he is injured then? Maybe even witness to Malekith using magic and becomes interested in the mystic arts as a result of that, perhaps as a way to try to cure his injury? that would set him up well for the movie a few years down the road if he's been dealing with this injury for a while. And it would not take too much away from Thor being a Thor movie, as I fear some of your other suggestions would, while at the same time giving a very useful lead in to the Dr. Strange movie. It would only be a scene or two cameo thing.