I still think the perfect spider-man game should include the following
-Free Roam, with a linear "main story" but with side missions you can do in any order at any time (think Fable, or how in SD you can choose any world in any order in each act)
-Indoor missions that are in a set area that would play like the pre spider-man 2 games.
-Replay ability (the best thing for me to do that, would be the inclusion of "break outs", meaning that throughout the game, defeating villains sends them to the raft, and once you beat the game, the game can allow criminal break outs so you can re-defeat villains. Imagine Rhino roaming the streets, or one of the Goblin's or Vulture soaring above the city wreaking havoc and you can find them or take them down.
-Team-ups. When breakouts happen, some villains may appear in the same area, thus causing you have to take down two villains together.
-Landmarks. Not only should all of new yorks landmarks be there, but so should majority of marvels (avengers mansion ruins, stark tower, baxter building, bugle, dr. strange's sanctum, etc... etc..
-For me i'd also like to have this have a "classic" feel, have it very 60's styled and influenced... sorta like a modern day 60's. So still very good and detailed graphics, but with a very vintage feel to all the character designs.