That said, there was one problem that kind of needled me throughout, and continued to needle me after I saw the film.
Maria is advertised as the tritagonist of the story, yet she's given no arc of her own. The two main leads are given conflict, flaws to overcome, and even a montage of themselves growing up--Maria is given none of these. There's really no excuse for any of these because Maria, by all means, should have all of them: the struggle of being a "proper" lady and meeting her family's expectations versus her own desires, a montage of her studying abroad, what imperfections in her character they could have chiseled in, I'm not sure, but it could have been done.
Instead, by the time we meet Maria post-timeskip, she seems to have everything figured out. She's defied the societal expectations through her pursuit of reading and self-defense, while also meeting them by becoming a "proper" lady. She stands up for herself and what's right without worry, even if it threatens her family's image, and basically has no problems of her own. This may have worked for many, just to have a cool female character to look up to, but it's kind of hurt by the fact that Maria isn't ever presented as someone who's looked up to by any of the other characters, thus establishing her status as "hero," and that she's damnably underutilized throughout the film.
Glossing over (or really, just outright erasing) Maria's arc could almost be forgivable if her character itself wasn't glossed over. But unfortunately, it is. All of Maria's best moments such as her leading the town into battle, turning down Manolo and Joaquim's attempts at romancing her, are all in the trailer. Her passion for fencing is only demonstrated a couple of times, and her love of reading is only given a passing mention; this in particular is bizarre, because her mentioning a favorite story of hers that, perhaps, mirror's the film's own story, could have woven into the narrative perfectly. As a result, Maria's finely-honed skills feel more like afterthoughts than they do things that are genuinely part of who she is as a person.
I see all these in-depth discussions about Manolo and Joaquim's arcs and characters and they just make me kind of sad, especially when the only discussion to be found about Maria's character, by comparison, is pretty brief "she's strong and independent and doesn't take anyone's bull." Which is fine, but man, how much cooler would it have been if her character had also been given an arc and characterization that was as complex as the leading men?