I think Swinton could be great in the role of the Ancient One. I've seen people online already declaring Doctor Strange "The first Marvel failure" because of this casting stuff. In reality, I doubt enough people will care that it will effect the box office or reviews, and I bet its a good casting choice from a creative perspective that will win over most people anyway. I'm sure Doctor Strange will be another great Marvel movie, with a great cast. People will probably be praising Swinton's portrayal once the movie comes out. I for one can't wait to see the movie.