By now we're all mostly familiar with the story of the Injustice fighting games, but if you're not then be warned that spoilers lie ahead.
Superman, after being tricked into killing Lois Lane, his unborn child, and Metropolis, falls well off into the deep end. It's an unforgettable story, detailing what happens when the world's ultimate Boy Scout becomes the world's worst dictator. However, I'm here to submit an alternate storyline that I feel would have hit home even harder. What if instead of Superman going off of the handle, it was Batman?
Batman as a whole is a far more interesting character than Superman is. Watching a man fight alongside gods, machines, and aliens all the while keeping up with and even outpacing them is inspiring. Batman isn't the strongest man in the room. It is his ability to outthink his enemies that makes him a match for even the strongest beings in the multiverse. And yes, I know we have already seen a take-no-prisoners Batman in FlashPoint Paradox but that was Thomas Wayne, not Bruce, so I'm willing to overlook that one.
With that out of the way, on to why Batman would've made the perfect bad guy in Injustice 2.
Batman Already Deals With Morality
Let's get this point out of the way since it's the most obvious one. Batman already struggles with his darkness, though Bruce's no kill policy always seems to be brought into the spotlight. Whether by his dead protege brought back to life Jason Todd or his murderous biological son Damien Wayne, Bruce is always having to defend his reasoning to keep his dangerous rouges gallery alive.
Maybe it's because he thinks he can help them. Maybe it's because he realizes that they share a common ground. For the most part people like Poison Ivy, Mr. Freeze, and Killer Croc are just trying to survive. Life dealt them a bad hand and they are simply doing their best.
It's these reasons why Batman going dark would be a whole lot scarier than Superman. Whereas Superman sees the good in humanity, Batman understands it for what it really is. That is why it was so easy to sway Clark's opinion, as he never really got it to begin with.
Batman Has Plans To Take Down The Justice League
It is commonly known that Batman has contingency plans. It is the argument that is used in almost every Batman vs X fight ever. Justice League Doom proves that Batman already doesn't trust the League and has a way to take each and every one of them down if the time comes. This is why Batman would have been such an entertaining villain to watch. Even with Superman unchained inn the first Injustice, Batman was still several steps ahead.
In fact, the best part about an evil Batman is that you wouldn't see it coming. Bruce is already slightly detached from reality, believing himself to be Batman at all times. To him, Bruce Wayne died with his parents. If he were to go off the deep end the heroes wouldn't see it coming until it was too late.
Batman's Villany Would Force Superman To Be Smarter
Clark Kent is at his best when he is in investigator mode. It's that brilliant side of Clark that wasn't featured in the Injustice games. They were so focused on his strength that they forgot that Superman is a very complex character. He has had his powers taken away on multiple occasions, and every time he has used his head in order to solve problems. One of the first things an evil Bruce would do would be to take Superman out of the equation. If not killing him outright, he would probably resort to de-powering him.
A Clark with no powers and nothing to lose would be an interesting perspective to explore. It would bring new meaning to the gear system as he would need something to give him the competitive edge.
Wonder Woman Would Have A Hard Choice
If Superman is the hero and Batman is the villain than the moral grey area would have to be Wonder Woman. It was easy for her to follow Superman to the dark side out of her love for him, but what happens when it's Batman who takes the plunge? Wonder Woman has already proved that she is willing to kill if necessary, taking Maxwell Lord's life when she realized that he had become too much of a threat. It would have been interesting to see whose side she would have fallen on.
Superman's Character Would Gain Depth
The best thing to come out of an unhinged Batman would have been the Superman who has to take him down. I never really liked Superman as the villain, if that wasn't obvious already. It's not like I hold The Boy in Blue to any high regard, it's just that he is kinda boring. All throughout the first Injustice he can't see that most of the people around him are just using his new found position to get what they want. He was a pawn pretending to be a king.
If Batman was the villain to force Superman to try and reason with him, I could see Clark trying different solutions. Sending Dick Grayson after Bruce. Exposing Bruce as Batman in order to try and sway the pull he is gathering. Maybe Bruce would hire Clayface in order to trick the public into thinking that Superman is a liar. A brilliant cat and mouse game that ends with Superman having to make a choice. Bruce isn't going to stop. He has out played Clark at every step of the way. The only answer Clark has left is to try and put Bruce down for good.
Injustice told the story of Superman's sadness turned into rage. However, I would have rather seen the story focused on how Batman's fine line between vengeance and justice shattered.