Tom Welling is too young to play a Superman at least five years older than the one played by Christopher Reeves. I don't know how anyone can diss Brandon Routh if he's an unknown. I trust Singer's casting decisions (except Rogue, of course) and I hope they don't force him to use Welling. Even putting aside the age factor and the fact that making Welling put on a costume would kill the little magic left in that pathetic show, I believe the movie won't be as good as it could be if the director is forced to use an actor he doesn't want.
