8. Superman & Batman Don't Need To Be Big Parts Of A Justice League Movie
While Batman drives the film's plot and gets a lot of solo screen time, his presence isn't too heavy in Mortal. He spends most of his time getting beaten up, and is constantly derided by the rest of the League for his mistakes. Batman is a strong enough character, though, that - given his various solo incarnations - his treatment in doesn't script doesn't diminish him. Superman, on the other hand, doesn't get much screen time at all, and there is little characterization for him. And that's fine. Like Batman, Superman is an extremely well-known character already. Both have already had more than their fair share of film outings already. A Justice League movie is a chance to let other DC superheroes shine, both to establish more franchises and build up the Justice League as something to rival The Avengers.