Honorable Mention: Hawkman/Hawkgirl
I'll leave this suggestion as an honorable mention because technically, it's not a team-up in the traditional sense, since these two heroes are forever intertwined in the destiny of the other. Either way, a film featuring the cursed lovers could be epic if done correctly. Centuries ago, Egyptian Princess Chay-Ara and her lover Prince Khufu were killed by a priest named Hath-Set, with a knife forged from an alien compound known as Nth metal. The properties of the metal and the strength of the duo's love created a bond between them, causing them to be reborn multiple times throughout the centuries. They are cursed to live forever, and find each other in life only to be killed and forced to begin the cycle again. The two spend their lives as Hawkman and Hawkgirl, taking flight using Nth metal's properties (which also give them super strength, regenerative abilities, and super strength). Carter Hall, aka Hawkman, is often portrayed as an archaeologist, which could give the film a fun Indiana Jones vibe. Mix that with the tragic story of the two former Egyptians and their ruthless, brutal fighting skills, and you have a recipe for a big budget blockbuster. Special effects are able to portray their iconic wings and power of flight without it coming off as campy, and if given the same grounded, realistic feel as Man of Steel, the film could deliver some truly emotional depth as well.