While I understand what you're getting at, my point is that I wouldn't consider Fiora to be Riot's attempt to move away from giving every lady in the League the same face. It's more that, from my experience, Riot doesn't give a damn about their women's faces and believes their bodies/outfits are the sole recognition point.
Hell, Ahri alone has four different faces - her in-game is based off her old splash art, then there are her current splash art, the Ahri vs. Morgana wallpaper that makes her look distinctly Caucasian and the look she sports in the Dawn cinematic. She also sports two different eye colors, blue in the cinematic and gold everywhere else.
In fact, even their bodies will often undergo changes to improve their sex appeal. Sona is petite with the exception of her breasts in most of her splash arts and models, but DJ Sona gives her an ass the size of Taj'Mahal.