DISCLAIMER: This contains personal opinion based on recent news. Nothing is official until Sony says so.
During the credits of The Amazing Spider-Man 2, it was teased that a [Sinister Six](movie:1274281) movie was in the works. Executives at Sony hoped that along with a Venom movie, the Sinister Six would help create a cinematic universe to compete with Marvel's. Well, because of the serious under-performance of The Amazing Spider-Man 2 and several other backstage issues, there may be sad news for the film's fans. The Sinister Six movie, along with the entire new Spider-Man franchise, may be dead.
The trouble was mainly started by Sony's disappointment in the film's box office performance. Though it did make $700+ million, Sony poured a lot of money into the film's production and marketing (over $300 mil total), and were reportedly expecting a billion-dollar movie. The movie has officially become the lowest grossing Spider-Man movie of all time.
Furthermore, the departure of co-writer Roberto Orci and the overall uncertainty about the series' release dates is sending Sony's only blockbuster franchise into a downward spiral.
Umberto Gonzalez of the Latino Review even tweeted: "RIP SINISTER SIX" yesterday, supposedly having inside information on Sony.
Even though nothing is officially cancelled, it's really no surprise that the franchise is in jeopardy. Thanks to producer Avi Arad and Sony's executive meddling, the original script was tampered with to tease a cinematic universe. Marc Webb originally wanted to make a movie with more focus on Peter and Gwen's relationship and Electro's story. Instead, the executives crammed in Sinister Six build up as well as a subplot where Peter tries to find out what happened to his parents.
As a result of the overstuffed plot, the movie received mixed reviews from critics and a better but lukewarm response from audiences (see above). It seems like Arad and Sony's attempts to go bigger and compete with Marvel Studios have backfired. With the Amazing Spider-Man series in limbo, Sony is likely in all-out-panic mode.
With news of Sinister Six coming before the [Venom](movie:372411) movie (and possibly The Amazing Spider-Man 3), it is likely that they are rushing the release of the anticipated film as some sort of comeback. However, even if they do end up making Sinister Six, the project is doomed anyway.
Sure, Rhino and Green Goblin were introduced in The Amazing Spider-Man 2,
but is it honestly possible to introduce Vulture, Mysterio, Doctor Octopus and Kraven the Hunter in one movie? It sounds like a recipe for rushed disaster, and it would likely perform worse than The Amazing Spider-Man 2.
Unless they can pull off a miracle, the franchise that they teased so much in [The Amazing Spider-Man 2](movie:508593) will be gone. No Sinister Six means no big movie to compete with The Avengers. On the bright side, this could eventually lead to Marvel Studios getting the rights to Spider-Man (just in time for Phase 4). So for those of you who want to see Spider-Man team up with the Avengers, keep your fingers crossed.