As a HUGE Superman fan, I'm pretty upset about the fact that WB is so intent on catching up with Marvel that they decide not to properly address Superman as a standalone hero. Their logic is purely money-driven. They decided to throw all the characters they can, starting with their two cash cows in the headliner, into the "Man of Steel sequel".
I'm afraid this movie is going to be solely for the purpose of establishing Batman and setting up the Justice League movie. I think Batman is awesome as a standalone character. I think Superman is awesome as a standalone character. But almost any time they've been put together, Superman is nerfed and dumbed down (especially in the Dark Knight Returns, which the Batman suit is based off) to idiotic levels. The Justice League: War and The Dark Knight Returns come to mind as prime examples.
I think pitting the two heroes against each other, as the title suggests, would be an injustice (puns, anyone?) to both characters and their fanbases.