Re: Marion Cotillard as Miranda Tate VIII (Team Frenchie Edition)
I don't think Miranda was underdeveloped. She didn't have an arc, really, she was a fully formed character, but I think she was a complex one, particularly in the subtle ways she related to Bruce:
Encouraging Bruce to trust the world, to do what is necessary, to return to philanthropy, and criticizing his apathy; chastizing Dagget for only caring about money; the fact that she is persistently seeking out Bruce to talk about the energy project. Picking up Rachel's photograph in the Manor, and saying, "I'll protect your parents legacy" and "Where's Alfred?", hitting all the right spots of his vulnerability. Her background as a child; her relationship with Bane, her conflicted relationship with her father, etc.
I don't see how you can say she is underdeveloped. Small amount of screen time does not equal underdeveloped. You can say she should have had more screen time, or the twist was stupid, or even if you want that Marion acted poorly (although I disagree), but she certainly isn't underdeveloped.