Well the best counter to Fiora is just picking up QSS. Riven has a lot of attacks that riposte will have little effect on trades.
That's why Fiora has to run scared in the lane against Darius and help other lanes.
I'm actually enjoying pointing out how wrong you are over and over. 8)
It feels good, man.
Uhh picking up QSS just to counter Fiora is terrible itemization.
Not trying to put more wood in the fire but just wanted to put my input on this Fiora vs Darius matchup.
In some aspects I find Darius actually a bit better in the early game since his kit allows him to just play safe and his naturally tankyness plus his Q heal helps him win trades and survive/turn around ganks. However I say it falls more on Fiora to make the lane in her favor since she has all the tools to do so. In a sense, I find the matchup fairly even but Fiora has to work a lot more harder to do so.
In the end though looking towards mid to late game. I find Fiora much more useful as she is a better splitpusher and can 1v1 easily when doing so. She also has more flexibility in teamfights, being able to pick out targets and getting off her ult heal does wonders. While Darius relies more on extended teamfights and him being in the middle of it which, on a high level, is hard to do since teams actually know how to peel and kite during teamfights.