It seems that with each year that passes, Emily Blunt’s profile increases. The actress starred in three films in 2014, two of which were major blockbusters (Edge of Tomorrow and Into The Woods), so it’s no surprise that the her name frequently pops up on fan casts for superhero movies - most recently for Captain Marvel. While playing the titular character would be her first superhero movie, it wouldn’t be her first experience for with Marvel Studios. In fact, she’s turned down two big Marvel roles in the past: Natasha Romanoff, a.k.a. Black Widow, and Peggy Carter.
While interviewing the actress, Vulture pointed out that she had previously involved with Marvel, having been talks for both Iron Man 2 and Captain America: The First Avenger. Explaining why she was unable to make things work with those two parts, Blunt attributes scheduling issues as the reason she had to say no. She described the opportunities as never coming together at "the right time," but also noted that she doesn't feel overly comfortable talking about the potential roles "because it’s not fair to the actresses who ended up playing them."
Scarlett Johnasson and Haley Atwell ended up playing Romanoff and Carter, respectively, and right now both of those characters have relatively prominent roles in the Marvel Cinematic Universe. Black Widow has had significant supporting roles in Iron Man 2, The Avengers and Captain America: The Winter Soldier, and will reappear in The Avengers: Age of Ultron. Peggy Carter, meanwhile, had the lead female role in Captain America: The First Avenger, cameoed in Captain America: The Winter Soldier and Agents of S.H.I.E.L.D., and will soon be at the center of her very own eight-part limited series Agent Carter.
While it’s hard to imagine anyone other than Scarlett Johansson or Hayley Atwell playing these characters, it would have been interesting to see Emily Blunt slip into the the Black Widow catsuit or fight in World War II as Peggy Carter. That being said, if things had worked out differently and Blunt had decided to play either of those characters, it likely would have prevented her acting in the big movies she's starred in over the past few years. Perhaps there’s a parallel universe out there where Blunt didn’t have the same scheduling conflicts, and now she’s either fighting alongside the Avengers or leading her own limited series.
As for her name frequently being brought up for Captain Marvel, Blunt has already pointed out that she has not been contacted in any way about playing Carol Danvers, but if offered the role, she would only accept it if it was "the right thing." The movie doesn’t come out until 2018, so if Marvel approaches her and she plans ahead, this could be her ticket to being a major player in the Marvel Universe.
You can see Blunt in theaters now, as she is starring in Disney’s Into The Woods.