BvS is a sequel to a movie that grossed 600M internationally despite the controversy and had a positive audience score, adds the second most marketable and iconic superhero character in all existence (Spiderman being the first) whose name alone guarantees success, and introduces the most well-known female superhero to the big screen in a environment that's begging for more female heroic characters.
And, despite what some of the lunatics on comic book boards would have you believe, the trailers didn't quell the hype. I'm not sure if it added to it, but it really didn't diminish it. Every reputable BO analysis I've seen predicts 1B worldwide gross. Every predictive indicator on the sites I've been on says this movie will be big. Fanboys can't remake reality with their ******** over a movie they didn't like. Sphincters aren't magic rings that can erase professional quantitative analysis.
You can think what you want, but I'm reasonably sure a billion will be reached. Because, to be honest, reaching the billion dollar mark ain't the impossible feat it used to be. If the movie sucks, it might not get much more than a billion, but it should still reach it. 
It's making it to 1.5B and beyond that the real test.