Telika: I think there's an open world Spider Man game somewhere, that is similar to the second Arkham game, in that you have a big city to roam and can interrupt side-crimes all over the place. Add some stats, some choose-your-side, and you've got the OP's rpg.
Enebias: If only it was so simple!
RPGs -at least, based on my definition, derived in turn from pen and paper ones- should have at least three features to be called such: character customization (not necessarily in looks, but necessarily in skills and traits), several widely different playstyle options and huge reactivity to choices in both the setting and the npcs. The farther you can go in making it with complete freedom of choice (something I believe impossible for an AI, so videogames will always be limited in this regard), the better it is. Alas, nothing can beat a good, human game master: with pen and paper if you want to do something... you simply do it! Everything can adapt, while programs are always closed between walls, no matter how much space you can find inside.
Yeah, in this context here we speak, implicitely, of cRPG, which are their own things, with their own limitations in terms of narration flexibility and all that. Actually, the OP wouldn't have much difficulty to find superhero tabletop RPGs, but I don't think that's what he meant.