John Constantine
Constantine is another fan favorite character who is heavily featured in the Injustice comics that is missing from the vanilla game. Constantine could function similar to how Doctor Fate plays in the main game being able to switch between close up attacks and ranged magic. The game probably doesn’t need more ranged characters but given Constantine’s infamous swagger it might be easier to overlook him spamming some magic fireballs. There could even be something fun like him flicking his almost constant cigarette at his opponent.
One of Injustice 2’s greatest strengths is the ability for the fighters to show off their personality in every fight. Between the clashes that happen mid-battle and the intro dialogue that opens every brawl, there is so much personality and story to each character in the most mundane of circumstances. John Constantine is brimming with personality and he is the perfect fit for the game’s approach. This is not even to mention how the gear system would affect Constantine. Adding him as DLC would be worth it just to see how many long trench coats variations NetheRealm can add to the game.