Maybe because it has Wonder woman, Superman and Hack Snyder is directing?
Well this film would have more sense witouth Wonder Woman, she is very out of place. Ofc this statement based on the trailer. But I do love the trailer, mostly the parts which are contained Batman action. Affleck seems to be was a very good choice. Still, I agree, this film would be better placed after a stand alone Batman and Wonder Woman movie. I kinda hope that the Standalone Batman film will be a bit smarter than this action and explosion fest, altough I cannot wait to see how Batman beats the crap out from Superman .I will admit that I think it's too early to introduce other superheroes, they really should have done two more films with just Superman before introducing Batman and Wonder Woman in their own films then tied them together like Marvel did with the Avengers.
Yeah, they seem to be aiming for a more "dark and gritty" atmosphere in the DC movies than the Marvel ones. And that´s fine, so each universe will have its own style and won´t be copying each other all the time.