I believe this because she is one of those sassy and unpredictable characters that everyone loves in a movie , she could be robbing some powerful magical items and gets took into custody by The Avengers and makes there life really hard work and is seducing the males of the team like Captain America and Iron Man and she could cause Black Widow to become really jealous and suspicious and they could have a fight which people would love because we haven't really seen the Black Widow face off against any other women in the Avengers.
In the end I believe she could come through and be a good person and actually starts helping the team. Also plenty of light skinned women have played dark skinned women and vice versa so it wouldn't be bad at all. Also ,mI believe the avengers are lacking a sassy joking person on the team who seems dumb but is actually very intelligent and also Felicia's past is a pretty rough one , breaking up with spider man and being raped and her dad abandoning her, that's a lot tongs off and could be made into a. Great story and I believe Beyoncè could pull that off perfectly with her sassy accent.