Here is the required post about the Avengers film, that Loki interrogation sequence, and themes of weakness, expectation, and vulnerability. When I say required, I mean everybody else is doing it, but that I will soldier on bravely, just like every other person on the internet in love with their own opinion.
So, Natasha’s most constant recurring themes are themes of control. Comic books are vast and largely un-sum-up-able, but every character has central metaphors that shine through multiple arcs and adaptations, and I think questions of control, questions of agency, are a huge part of her equation. Duane Swierczynski is the current writer on the DC series Birds of Prey, but he also did a run on Black Widow, and this is something he had to say about it:
From the very beginning, she had no say in her own destiny, which is a very noir, very dark kind of outlook on life. And yet, she fought back from that and has now taken her own life in her own hands again. I guess I respond to those kinds of characters. Characters that seem screwed, who are also talented but are put in a difficult position and who fight their way out of it. That’s what appeals to me about her. Despite the convoluted, difficult life, she’s come out on top. And now her mission, the way I see it, is that she wants to free other people from being controlled and used. That’s her thing, I believe, and why she is equally super hero as she is a spy.
Natasha is someone whose specific skillset was forced upon her, something beyond her immediate control, but it’s also the only means she has to take her own life back.