Frankly, I have no idea about significance of V-shape in regards of realistic plate armor (all I learned about armor design was through running this blog). Seems like your question is more suited for an armorer, like Ryan ‘Jabberwock’ who wrote this article.
Would this actually work in real life as real armor? Probably not? But I’m not sure that’s the most important thing to focus on, unless you’re making a gritty, realistic, historically-accurate work. For fantasy? COOLNESS is what counts. I’m all for seeing non-sexualized, diverse ladytypes with functional armor, as long as the coolness factor doesn’t get lost!
A naturalistic story tells a story that is completely plausible in our world. No wizards, no dragons, no secret vampires, no alien invasions. Telling a realistic story is telling a story that is logical and consistent and makes sense (even if the setting is in a fictional world or in a reality very different from our own).
And that’s one of the basic things BABD aims for: promoting female warriors who dress in believable and protective manner, not necessarily realistic/naturalistic.
We criticize bikini armors, boobplates etc. not specifically because they’re historically inaccurate (which they are, but so are dragons and orcs). We criticize them because they’re inconsistent with how most fictional settings work.