Mine would be another Assassin's Creed game, but set in modern times. There's plenty of different ways of having the game set location wise: the Syrian Civil War, the slaves in Pakistan, India, and/or China, or a South American country that's being ruled by a dictator. I'm not sure what could be added in terms of abilities, weapons (besides machine guns and nukes), side missions, or story plot, but I know that there could be a way to do it and make the game work.