Increases the stacks by 2 when hitting champions? Her E grants her a massive attack speed buff so it is not even needed. You gain more stacks hitting champions too, and only one on monsters and minions.
The health regen is also really good. Since Fiora has Riposte, a passive +15 damage, AND health regen.. She's immune to basic attacks when using Ripose PLUS she outputs way more damage AND she is basically reducing all damage when fighting an enemy. She's wicked powerful early game, which can really make her strong late-game.
Fiora's ultimate is odd, but I believe it's perfect the way it is. People can take flash, tier 2 boots, and her ultimate at level 6 and dive plus get away with it.
Here you're just asking for buffs, which Fiora does not need since she's really powerful at laning, sustaining damage, team fights, and overall offensively she's super strong.
THE ONLY THING IF ANYTHING that needs a buff is her Q, which has LOW base damage and a LOW AD ratio. Early game using her Q twice is a bit more than her base attack damage, but late game it's much lower so it's only to be used as a chasing spell. This is why they should buff the ratio to 0.6 bonus attack damage.
Fiora is strong, only the Q is underpowered. But defensively, offensively, and utility-wise, Fiora is a strong Fighter champion.