"An amateur artist imitates, but a mature artist steals" - I was told that by another artist at one point. Of course, I don't view it as stealing often more as an homage. For example, the movies "Fistful of Dollars", "The Sword and the Sorceror", and "Last Man Standing" are all the same story. A lone drifter bad-ass wanders into a podunk town where there are two factions warring over a single resource (in 2 cases the town's only source of water). The lone drifter gets involved playing both sides against one another and ends up the victor and gets the girl and all that. Of course all three are set in 3 different genres. One is a Western, one is sword and sorcery and one is set in a depression era Texas town. The point is, it is hard to find an original story anyway so if you want to use a storyline seen previously, dust it off, make it your own, pay homage to the original but put a new spin on it.
Why do I go into all of this? I just watched "The Wrestler" this weekend. Loved it. Loved everything about it from the acting, cinematography, the Springsteen soundtrack. Anyway, if someone were to take that storyline, substitute a broken down superhero for the wrestler and craft a really solid "world" around the characters were superheroes existed (like the world in Watchmen or Wild Cards) then it could be a great speculative fiction story.