Ever since I started to read the manga, Mikasa was my least favourite in the main trio. Her backstory was interesting, how she gained strength after the death of her parents and how she became bonded to Eren, but unrealistic because they were nine. Her biggest psychological evolution happened when she was a child and was shown in a flashback, so it is hard to feel her evolution in the story, unlike Eren, Armin, Historia, or even Bertolt. My thought was that besides giving Eren some space, she didn't have much to improve.
But the time skip and Eren's deeds happened. We saw a grown Mikasa still very devoted to Eren, but who criticized more his choices, and the best way possible. I could feel how torn she was to see the person she loves the most slaughtering innocent people and destroying everything on his way. And since we know how important Eren is to her and how much time we spent with Mikasa, I felt bad. And then happened the moment Eren tells her he hates her. There is a theory which says he didn't mean it, but let's put it aside and focus on Mikasa's reaction.
I must say, for all the times my eyes rolled off when Mikasa had her 'Eren first' moments, I was sad with her, because it was like her world was falling apart. And we got to see Armin angry and ready to punch his best friend. Mikasa and Armin's friendship isn't the most important but they have good moments. When he panicks after his first kill and she tries to calm him down, when she tries to have him get the Colossus powers. For this one it was one of the moments I really felt she was doing something for herself and not for Eren.
Ever since that moment, you can see how torn she is between her feelings towards him and her duty to take him down, as she cannot follow his path.
What I am saying is not only I am glad Mikasa is undergoing this, but the way it is shown in the manga. Because it really changed the opinion I had on this character, and now she is my favourite in the main trio.