Funny that you mention Batman being a bystander when these battles take place with the other worldly characters. BVS was on the TV yesterday and the part of the movie where they were battling Doomsday, Batman was just chilling as Wonder Woman (she was definitely kicking some you know what in those scenes) and Superman was doing all the fighting for the most part. Yeah he didn't want no parts of that. hahaI just love how Snyder managed to give Batman such a good role in the final battle against the Parademons. This is often his problem when dealing with supernatural beings like Steppenwolf, physically he can't really. But I'm always impressed how much time Zack gave to him to be in the action as an integral part, and not simply forgotten as the others deal with Steppenwolf.
That whole final act was excellent !