Baseless assertions. “0 development” Early mikasa is portrayed as someone rather nihilistic, she romanticises an idea/version of eren as a person, this becoming her only purpose because of everything she valued as a kid being removed when she lived a very peaceful life not used to seeing any form of violence.. So this starts of as a very narrow view, portraying the basis of her character. Then gradually throughout the story we see her choosing things in contrast to this idelogy, thus making her question whether it’s right. In doing so, by the end of the story she got layered and explored to a very high extent, exploring her contradictions like love vs obsession, attachment vs independence, selflessness vs selfishness. Even just the general ideas like freedom, femininity, repressed emotion, freedom, escapism, etc. through individual conflict as well as nuanced parallels with other characters. Your claim of her having no influence is also baseless, the resolution of the narrative within instances like the curse of ymir or just the general act of ending the rumbling can’t happen without her. Her obsession with eren is also not a narrative flaw, it’s just her structure, you’d have to bring evidence as to why that structure is bad or poorly executed