7. No Robin And/Or Nightwing
There have been multiple rumours suggesting different actors being cast as Robin or Nightwing in this movie. Going off the previous point, including too many central Batman characters will take away from the focus of this being a Superman sequel. In Superman: TAS (which had established Robin and Batgirl in previous shows) there is no mention of Batman's costumed sidekicks. Alfred performs all the necessary support in the story. This would be especially frustrating if the filmmakers chose to include Nightwing as that particular character has a long history which couldn't be explained in a cameo appearance.