How to fix Fiora
Make Q cost 40 at all levels so she actually has mana issues (her max rank mana cost on Q is 40 so this doesn't hurt her late game at all).
Remove her attack speed slow. It makes no sense to have this attached to an ability that can literally block ults. It's particularly difficult to avoid as a melee champion. And this is just extra power she doesn't need to have. She already can proc a massive heal, does %true damage so you can't itemize vs her and between her W and Q prioritizing vitals, it makes disabling her via various anti-DPS spells (AS slows, MS slows, etc) virtually impossible. A well played fiora has almost no windows of weakness and that's honestly bullshit.
that made her early game more survivable and
which is far too strong right now for anyone that can use it.