No. I wouldn't do this. This is kinda making her stronger late game than she is now. She's supposed to be early gamed. Plus dude. Then everyone would probably build longsword first.
Plus I do not think the scale of the AD change every level. At least I'm 80% sure it doesn't change over levels
Fiora right now: [Starting with LS: 71] [Late Game with full Q with LS only:111] [late Game full Q with 200 AD: 225]
With your change: [Starting with LS: 26] [Late game with full Q and only LS: 66] [Late game full Q with 200 AD: 180]
71-26=45 111-66=45 225-180=45
In every stage of the game. you would have a shortage of 45 damage compared to her current self.
She would barely be better late game. And a lot weaker early game. This is not a balanced changed.
And your idea about changing her W would make her even weaker. Then she wouldn't be a counter of Riven and Riven will have pretty much the dominance of top lane. Her W changed to only atk spd reduce doesn't do anything in the top lane anyway, since most top champs are already slow in atk spd. Plus blocking a Auto attack would be quite hard sometimes considering you would have to predict if they're poking you or not. Considering her W only blocks cc and debuffs in the 0.75 second after she uses W. It's already a feat that you can pull this off all the time.
Her passive only activates if you manage to complete it.
