Respectfully, I have to disagree. Whedon has stated that Widow's story will focus on her being a spy and her lack of a moral compass. Add to this all of the information on the Black Widow programme we have from Agent Carter and the vision from SW and there are signs that the traditional Widow storyline may occur in this movie.
Fury is no fool and he trusted both Hill and Coulson during TWS story. Why trust them and not Widow? He knows what happened in her past and that she lacks a moral compass and he said she 'is comfortable with anything' in the movie. But by knowing her past, he also knows that her worldview isn't her fault.
Whedon is famous for using relationships to destroy the lives of his characters (Buffy and Angel being classic examples) and many of his strong females are complicated and duplicitous (Faith). Plus with Civil War approaching he will probably include a number of storylines where characters make decisions that damage the team (ScarJo has said Widow's choices will have consequences). No one needs to be shown as a backstabber, just misguided.