It's been recently speculated that if another Iron Man film were to take place, then Robert Downey, Jr. could be replaced with another actor or character; now it appears that there might be a theory on who the character would be for the replacement- Black Widow.
Last Wednesday, studio president Kevin Feige was at a press conference to promote Captain America: The Winter Soldier where he discussed the possibility of Black Widow ever getting her own film. Coming Soon posted what Feige said and how optimistic he seemed.
"I think the idea would be great," Feige said. "We've got various outlines and ideas of where to take that. As Scarlett already said, there's a big element that explores her back story in an upcoming Marvel feature. The question really is, 'When will we take her out of the ensemble and have her do her own thing?' As you saw in [Captain America: The Winter Soldier], as you'll see in Avengers: Age of Ultron, she's really the key to so much of the plot development."
Considering that Black Widow is connected with Iron Man, this creates a high possibility that if Robert Downey, Jr. didn't go through with another movie, then Black Widow could take over with her story.
IGN posted a video with rumors of another Iron Man film. Chris Tilly, the host of The Superhero Show revealed his interview with Iron Man 3 co-writer Drew Pearce.
"I said, 'Would you direct an Iron Man film in the future and he almost had to stop himself," Tilly said about Pearce. "I felt like he was saying that Downey Jr. doesn't want to do another one in which case he doesn't think there'll be another one or certainly not for a long time."