1. Spider-Man
Peter Parker is a nerdy high school student who was bitten by a genetically modified spider and gained spider-like superpowers. He can climb walls and has a perfect sense of balance. He can shoot webbing from his wrists to swing from, and to catch and bind opponents. He has a sixth spider sense that alerts him to danger. He also has superhuman strength, speed and agility. For the most part Spider-Man works as a solo crime fighter, but he also sometimes works with partners and teams. He has had a significant partnership with Iron Man, and for a time wore a special Stark designed armour, dubbed Iron Spider. He has been a reserve member of the Avengers for a long time, and is currently part of the main Avengers team.
Why does he need a miracle? The film rights to Spider-Man are currently owned by Sony. Sony and Marvel would need to make a deal for Spider-Man to appear in the MCU, which isnt outside the realm of possibility. Sony and Marvel did make a deal for OsCorp Tower from The Amazing Spider-Man film to appear in the New York skyline in The Avengers, but it did not eventuate due to time constraints. The Amazing Spider-Man 2 is scheduled for release in May 2014 with plenty of time to be included in The Avengers 2, if a deal can be made.
What do you think? Is there another Avenger you would like to see in the MCU?