You ask for examples, but have no refutation of my statements? At least describe what makes those Gentiana or Luna designs 'great' in your opinion? What is there that makes those good character designs? "Great and elegant" describes a lot of dresses and outfitsso what is visually interesting, distinct or even fashionable about Gentiana or Luna?
Fan Bingbing, Marchesa: a princess-like style and dress, but using a theme of nature, it is much more visually pleasing and arresting than Luna.
Again Fan Bingbing, this time Ralph & Russo: pink dress with green blossoms and birds, works well with her skin tone and has the feeling of 'wings' from the sleeve design. Much prettier than bland white dress, yet can also convey the exact same "elegance".
When I speak of costume that says something about 'character', it is when what the character wears reflects the character's purpose, personality, and the image the character is trying to put forth. The lady who crashes your boardroom meeting dressed like this is not just going to bow out.
One look at this dress, the character who would wear this kind of dress is apparent immediately: femme fatale.
With Gentiana standing there in her character render, what does her visual design say about her? That's right: absolutely nothing.
FF15 costume/character design has been incredibly bad considering how many styles exist in a contemporary time for the character/costume designers to draw from. Repeating constantly, "I don't know what you guys are talking about, everything is great" is just a state of enclosing yourself in a bubble.