Even as a prequel, a Black Widow movie seems hella unnecessary now. shyt would've made sense and fit in years ago but not now. That slot could've gone to any one of the newer characters.
they truly only have one route to go with this . . otherwise there is no point in seeing it . .in the comics we find out she has multiple clones . . that's the only way I would care to see a prequel here is a tidbit from the comics
---------------
After the original
Black Widow was killed by
Captain America, the
Black Widow Ops Program created a clone of her. Unbeknownst to her handlers, she retained all the memories of her former self thanks to
Ursa Major having bribed
Epsilon Red, the Red Room operative in charge of granting Red Room clones selected memories from their original selves. Her superiors tasked Natasha with targeting the remnants of both
Hydra and
S.H.I.E.L.D.,
[1]which drew the attention of her former lovers,
Hawkeye and the
Winter Soldier. . . .
---------------------------
if they go this route its nothing but waking up another clone and having her retain the memories of the previous Natasha anything other than this i won't care to see :\