It's no different than A Realm Reborn (which gets praised often) where all female armors seemingly have cleavage or their entire midriff or something revealed all of a sudden compared to male armors of the same type. Dragoon armor in FF14 ARR is revealing for females compared to males.
FF11 in comparison mostly have parity between male and female armor with exceptions that make sense (like Dancer Empyrean Armor which has a vast difference but that's because it actually fits the theme).
Now, I'm not saying I don't like it but if people are criticizing the FF15 Dragoon Lady, they should also criticize the armor designs in ARR. Half of the female armors in ARR have a lot of exposed areas compared to the male characters of the same type.
The difference between them is, in ARR Dragoons (and everyone, really) have multitudes of options to choose from. What's more, your character is representative of you, so you have agency over what you choose to glamour or equip. There are a great many female players in ARR, the sexiness is not an issue because they have agency over it, and the NPC characters who are important in the story are in fact not hyper-sexualized with the exception of Shiva who has always had a very sexual design in FF history. This is not a simplistic 'bad vs good design' issue, but one of relation and representation, and is, as you can see by the past few pages, a very tough thing to talk about on the same page.