Regarding Dottie’s redemption arc
(which will always exist in my mind even if we don’t get a second season or no Dottie if we do get a second season)
Like, Peggy finds a way to get Dottie away from Leviathan since they were going to put Dottie out of commission because Dottie made a split second decision to not kill Peggy and instead shoot the person holding Peggy captive. Peggy doesn't know why Dottie did what she did. What Peggy does know is that the reason for Dottie’s actions must have been a powerful one to have overcome years of brainwashing and abuse disguised as training.
But Dottie doesn't stick around after. Dottie disappears maybe out of fear because no, she didn't really enjoy the things she was forced to do, but that was her life, and what is she if she's not a Widow for Leviathan?
Dottie’s barely a person and most of her personhood is defined by her love of fancy automatic weapons and her weird incomprehensible fixation on Agent Carter. Defying Leviathan was an act of insanity, a decision that part of her mind made without consulting the rest of her brain. So Dottie stays out of Peggy's way, but never really leaves because Peggy is key. Something about Peggy made her act the way she did and if she figures out what it is maybe...maybe she'll...
Anyway, Dottie watches Peggy, sees her kindness in action, her righteous fury burning bright at the injustices around her. Dottie sees her strength and determination and a multitude of other confounding, beautiful qualities.
(She also sees how Peggy and Angie interact and it makes something sickly and painful twist in her belly and sting her heart. She wants to get rid of Angie, imagines how easy it would be with her skill set. But then she remembers how sweet and sharp and exuberant Angie is, how she always offered to help Dottie for no other reason than Dottie acted like she needed it. And then she imagines Peggy's reaction to losing Angie. Dottie buries her first instinct, tries to smother it because those are Leviathan thoughts not Dottie thoughts and maybe Dottie isn't her actual name but Dottie is the person Peggy thought was worthy of saving, so maybe she can keep the name and try to be the person Dottie was supposed to be)
During her watch over Peggy, she occasionally steps in when Peggy needs back up. If Peggy is severely outnumbered—even though she has seen her take down a room full of men single-handedly—Dottie will quietly slip in and take down one or two of the opponents and slip back out of the scene. (Peggy thinks she's imagining the flash of blonde hair she sometimes see out of the corner of her eye during her fights; when she finds extra men subdued she didn't remember knocking out but Peggy chalks it up to losing count in the heat of the moment, at first).
That gets Dottie into the habit of intervening when other women are in trouble. Women she finds pinned and crying in alleys by groups of jeering men—laughably easy to dispose of—or following pushy men who follow women and make sure they get suitably detracted from finding the women's homes. She does this on her own; nobody but herself tells her to do this but she feels better, useful, afterwards.
Then one time, she finds a little girl crying, bruised and bleeding, because the other girls called her a foreigner because of her accent and shoved her onto the rough muddy pavement. And Dottie gets overcome by a fury she had never felt before; these girls are hurting each other for no reason, their lives don't depend on their ability to hurt other girls like Dottie's had. They never had to kill other girls to prove they're worthy of living. Why do this? Why hurt each other? Girls deserve better than this, Dottie had deserved better than what she was forced into. The realization was like getting struck by lightning. Dottie had never seen herself as a victim, never thought of the other girls at School as victims. But they were. They were girls who were treated as tools.
Peggy thought Dottie was worth saving, doesn't it stand to reason that the other girls in the Widow program (and they were just children, small, powerless and scared) deserved to be rescued as well despite the blood on their hands? Dottie thinks she's found a mission, a good goal that would let her feel again and would put her talents to better use. It's a goal she thinks Peggy would approve of.