One of the long-beloved exercises in comic book fandom is picking out the dream movie versions of your favorite characters, and with the announcement of James Gunn's new "Superman" movie, the fancast wheels are spinning like mad. It's a major bummer that Henry Cavill, who played the Man of Steel in the DC Extended Universe, won't be back in the red cape and spandex for the new film, but since it's focusing on a much younger Clark Kent/Superman, it only makes sense to cast someone else. As