"now how am I supposed to defend fernando alonso again" you're all into war criminals until they start doing war crime again smh. was this not the man you called a shakespearean villain? I'm not defending him, I'm giving him a gun and watching what happens.
I'll be honest, I am mostly influenced by fic for her. @tielan handles her with finesse, competence, and love. I have not seen all of her appearances. What I have seen leads me to label her as more level-headed in her situation evaluations (Natasha jumps to worse case scenario too fast for instance).
Maria has the Coulson ability to follow orders, and hedge them within certain parameters as needed. She is a little bit colder; it's easy to see why Fury picked her as being closer to that analytical necessity.
I came at her with a finite level of comic awareness behind me, and felt the casting could have gone better, until I actually watched her. The actress seemed to really think out who this character was and USED it in body language, phrasing, looks… all of it. So my apologies to her, for past me's assumptions.
I would have loved to see her team up more strongly with people outside of SHIELD more (maybe she did in bits I have not seen). I would still be down for her throwing together a different task force of her own. (what death, no there was no death).
All in all, she is a solid character, and could very easily have been used as a lynch-pin to different stories than what they used her for.