He wasn't in any of the Injustice games and in the comic he was seen in a vision of Superman's life had things gone differently. He didn't appear in the second Injustice game, so why not have him appear in the third instalment of the game? Red Tornado In the first Injustice game, he was seen battling Giganta in the background of the outside area of the Hall of Justice. Why not give the Amazonian battle-sister of Diana Prince a role in the game? She could fight alongside Hippolyta in reclaiming Themyscira. The thing about her is that she never makes an appearance in either comics or even a cameo in the games. Maybe have her make an appearance to not only scold her daughter, but also take back the mantle of Queen of the Amazons and have the unfortunate duty of beating her daughter bloody for it. The mother of Wonder Woman certainly had her disappointments about what her daughter did in the Injustice universe. So why not have the noted detective of the occult in the video game? Hippolyta
He made an appearance in the Injustice comics as part of Batman's insurgency against Superman but was not in the game. Since she was in the comics, having her would be a nice addition to the Injustice series. Though she was not in the games itself, she was in the comics and had joined sides with Batman against Superman's regime. So why not put him in as a regular character? Wonder Girl Once in Arkham Asylum stage in the first Injustice and in the Batcave in the second game. The Crocodile man himself has made cameos in both Injustice games. Here is a list of the many ideas for who I think should make an appearance in the game. There has been a lot of discussion around the internet about a 3rd instalment of the popular Injustice series.