User blog comment:ADour/Official title for Marvel's The Avengers sequel announced!/@comment-4651179-20130721032030/@comment-3317214-20130722010743

That's why I said "a new Spider-Man".

No, they wanted to rush into a Justice League movie when they said they were gonna fast-track a Man of Steel sequel for 2014, and still go ahead for Justice League in 2015. Now they're easing into Justice League.

Besides, it's not unprecedented. Didn't they introduce Batman/Superman stories into the comics universe and the animated universe before the Justice League as well?

It is a Superman/Batman spin-off, and acts as a sequel to Man of Steel, just as the Avengers does to Thor or Captain America: the First Avenger or something...