Pick and choose which nerfs she deserves. I feel that her Q needs nerfs just how Darius got the same.
Increase the mana costs just how Riot did to Darius to her Q. 20 / 25 / 30 / 35 / 40 MANA -> 30/35/40/45/50 MANA
Reduce 60% cdr when hitting a Q on a champion to 30%, let it only be 60% once it hits a vital.
Fiora does not get 60% cdr on her Q by simply hitting a minion, it will actually be 30% instead
Nerf the living hell out of Riposte by attack speed reduction by levels. 26% lv 1 /32% lv 2 / 38% lv 3 / 44% lv 4/ 50% lv 5 as opposed to 50% lv 1
Increase Ult's Mana Cost by 100/100/100 to 100/125/150
Reduce attack speed scaling from 3.2% per level to 2-2.5% per level.
Reduce Base Movement speed from 345 to 340.
Reduce Modified damage from E to 120%/140%/160%/180%/200% instead of 140 / 155 / 170 / 185 / 200% 」
It's honestly not that hard to just pick on of this and send her win rate below 50%