DC/Warner are really trying really hard to compete with Marvel.
Batman vs Superman suffers from telling too much story. They don't have the patience to try and build a universe like Marvel did.
They just tried to do it all in 2 movies. Man of Steel and Bat vs Sup, it's stupid.
It's another case of executives trying to straight up copy things that have worked for other successful companies. But they aren't willing to put in the effort or time to lay down a solid foundation to base their cross overs off.
Marvel's actually good at it. Look at Daredevil and Jessica Jones. Daredevil didn't jump into the 2nd scene to try to jumpstart Jessica Jones. They haven't even met yet in the netflix series. DC/Warner just blew their load with Batman vs Superman.