Sticking with popular superheroes, The Flash TV series is doing exceptionally well, and this game could play off of that popularity. Sure, it may be a little bit harder to develop this game, but I think it could be great.
You play half the game as crime lab specialist Barry Allen, searching for clues a la L.A. Noire and then, once you have a lead, you race through the city and fight bad guys. You could even have side quests where you help out the fire department and police department throughout Star City. The controls would just need to be slightly tweaked from DC Universe Online and you'd have some great gameplay to boot.