3. Carol Danvers aka Ms Marvel
In the Ultimate Marvel comics universe, Captain Carol Danvers became acting Director of S.H.I.E.L.D. when Fury disappeared. Unfortunately, this version of Danvers does not have any superpowers. The mainstream Marvel Comics Universe version of Danvers is one of the strongest female characters in the Universe. She has superhuman strength, speed, stamina and durability, the ability to absorb and project energy and the ability to fly. The Marvel Cinematic Universe has drawn from both the mainstream Marvel Comics Universe and Ultimate Marvel Comics Universe for inspiration. The S.H.I.E.L.D. series could use the Ultimate Marvel connection to S.H.I.E.L.D. with the mainstream powers to create a new Ms Marvel. By bringing Ms Marvel into the S.H.I.E.L.D. series, it would also make it easy to bring her into The Avengers without a lead-up film. It would be interesting to see how Stark and Rogers would cope with having a female on the team as strong as they are.