Well it seems that Natalia Romanova is playing a more prominent role in Captain America Winter Solider than first suspected. This featurette shows that Captain and Natalia work very closely together in the upcoming movie and it seems to expand on her character much more than from Avengers. Which I think is a good call as Natalia played a key role in S.H.I.E.L.D, in the comics, and the early cartoons.
Marvel’s Captain America: The Winter Soldier – Featurette 2
Captain America: The Winter Soldier Synopsis