This film is so hard to read. Is this a MoS sequel? Is this a Dark Knight sequel? Is this an original film?
I think you have to use MoS as the bar of success, so I chose 700-800M as the success line. It's really hard to read other than that. WB has not done a good job selling this and the whole thing seems forced. Affleck's biggest B.O. films were over 10 years ago with Pearl Harbor and Armageddon.
There will be the curiosity factor that will be in it's favor, so I see a potential big opening, but a lot is going to depend on the reviews. Snyder has not been associated with quality films or being a good director, I don't know how much slack he's going to get, and Goyer's MoS script was horrible, he absolutely has to do better with this, and he needs serious help.
If the films opens the same or less than MoS then the film will be seen as a disappointment.
It does not have to match Avengers, or even be a billion dollar film.