Cool artwork.
Doesn't really strike me as "Fiora" though. Fiora is clearly full of herself and think's she's amazing judging by her sound set. Extremely confident. Outside of her sexy skin, her outfits tend to be at least practical enough to not distract from the fantasy of her being a swordy champion that messes things up at close range either. The heels and skin-tightness obviously isn't the most ideal thing to be wearing, but it seems more over-the-top catsuit spy gear than completely unpractical Sona dress. And this is much more on the completely impractical Sona dress realm.
She seems pretty sad and dainty in this artwork too, and I am not having an easy time imagining her dancing on people's faces and lunging around with that robe. The exposed shoulder makes it seem on the verge of a wardrobe malfunction with just casting magics at someone, let alone swinging her arms wildly while booping things over the head with her sword. The split in her robe near her hips also seems akin to malfunctions mid-ult when she's flying around. I have problems not imagining the Marilyn Monroe fan deal going on there.
Think it needs to be more like Riven, Tryndamere, or Talon's oriental skin to seem like an idea Rito's got to run with. More prominent armor elements, cool pants.
I would imagine she would be wearing something more like this:
http://filmfork-cdn.s3.amazonaws.com/content/art-crouching-tiger-620x349.jpg
Not exactly open-ended and allows for more mobility.
I don't think this would fit her animations and her fencing style too well.
So many posts about fiora skins this week... take note Riot the community wants one
gender bender yasuo skin

Looks more like an Akali skin.