Suddenly, I'm somewhat less concerned about the amount of characters allegedly being introduced in The Amazing Spider-Man 2. Today, Sony announced the release date for not just the expected The Amazing Spider-Man 3, but also for The Amazing Spider-Man 4. Having 4 films to spread everything out gives director Marc Webb much more room to play with the characters, so I wouldn't be surprised if some of the confirmed characters are merely set-up in the next film or even just teased. The Amazing Spider-Man 3 is slated for June 10, 2016 and The Amazing Spider-Man 4 is set for May 4, 2018. So yeah, it seems like you shouldn't get your hopes up on Marvel Studios getting those rights back any time soon.
The Amazing Spider-Man 2 is scheduled to hit theaters May 2, 2014.