- Batman is a proven box office commodity.
- Man of Steel performed very well when taking realistic expectations into account, and it's performing especially well in Blu-Ray/DVD sales.
- It's the first time these two characters are appearing on the big screen together in 70+ years. The novelty factor is going to be there.
- Despite the *****ing and moaning regarding Ben Affleck, people will show up out of curiosity if nothing else.
- The turnout for casting calls today is rumored to be anywhere from five to seven thousand. Interest is clearly there.
Frankly, Batman vs Superman is about as much of a "little-to-no risk" project as WB can possibly get. It would take a catastrophically bad film for it to not be a huge financial success. The kind of movie that people walk out of halfway through.
And people should stop acting like Marvel has nothing to lose here. A weakened box office draw for CA3 could slow their ever-building momentum. And if BvS did come out on top box-office wise, does Marvel (or more importantly, Disney) really want to deal with article after article about Marvel finally stumbling in the wake of a DC project?
And no sane movie studio would be willing to take a hit on potential profits just to make a point. Especially The Mouse. Despite Feige's chest-puffing comments, Iger's remarks about them "struggling with it" don't surprise me in the least, and I can very easily see CA3 moving.
EDIT: Alan Horn, not Iger.