There's a lot more to it than what's in the article. The amount of legal issues that keep Batman and Superman from appearing in the same movie are plentiful.
Besides, if they wanna go for continuity, it'd have to be Ryan Reynolds, Christian Bale and Henry Cavill. Ryan Reynolds is going to be a shit Hal Jordan, nobody knows about Henry Cavill in the role yet, and Bale's Batman is too dark to be in a movie like that, I think. It works in the comics, but not in a movie.
