Injustice 3: 10 More Characters NetherRealm Must Include

Hawk & Dove would make for an excellent addition - their being a pair meaning that they could act as a tag-team, the player switching between each of them on the fly. The characters' different personalities could be expressed in their fighting styles, Hawk's trademark anger lending itself well to more aggressive, brutal attacks and Dove's relative tranquillity allowing for a more measured and precise set of moves.

Implementing this tag-team mechanic wouldn't be particularly difficult for NetherRealm as well - it could simply function like Nightwing's staff, which changes the character's fighting style depending on which mode it's in.

Aside from the uniqueness that such a mechanic would bring, Hawk & Dove have long had a cult following, but have begun to grow in popularity because of Titans, so including them in Injustice would only serve to further add to their ever-expanding fandom.