Have you not watched a single interview? In almost every interview they are asked this question. How Batman will be able to stand his own against superman will be explained in the story mode.

Or y'know, you could disable custom..

Lazy ass developers

I'm kinda on the fence about this too, the game with season pass is gonna cost 75$, not even counting the DLC costumes and other stuff. But then again 10 months is quite long to wait...*Sigh* such a hard choice..