Originally Posted by cherokeesam
At least with the Spider-Man/Wolverine arguments, we *know* that other studios have the rights to the characters and have built box-office franchises around them. As for Wanda & Pietro, NOBODY has put them on film yet. And Feige specifically stated long ago that they're legally available to both Marvel Studios for Avengers AND to Fox for X-Men.
they're also established classic Avengers characters.. why wouldn't they be used in an Avengers film?