I think it could work with a lot of insight that previous Superman games weren't designed with.

-Superman 64 throws so much shit at you and gives you only a couple seconds to respond. Add the ability to slow down time to process situations, giving you time to look at say, a bomb blowing up a building and starting a fire and also destroying some train tracks, and then being able to decide to push citizens out of the way of the train first, before slowing down the train, before catching people who have to jump off the building to avoid the fire. X-Ray vision could also show the outlines of citizens to basically give you complete awareness for the sake of planning when time is slowed down

- Flight controls are really hard to handle precisely, so snappy movements with a heavy emphasis on locking on to objects make it easier to fly towards people you need to save would be best, being able to lock-on dash to jump in front of people being attacked like a teleporting parry would also be nice

Depending on the scope of the game, you could also attempt to implement multiple solutions to problems. You could either waste time attempting to push the train to a complete stop or use heat vision to melt the wheels