I really really liked the old fiora, so i may be biased. But the new fiora i see no reason to build AD. with %max hp true dmg i feel she will just turn into a tank that kills other tanks and has no CC so will never be a real tank. Anyone who knows better able to comment on what her AD scaling will be like? What is the incentive to build AD?
We don't know the numbers yet, so reserve judgment.
Fiora's incentive to build AD?
Same incentive as 
now.
She'll probably start with a 
and go into tank-mode with 
, maybe even throwing in a 
for more healing on her ult (probably AP scaling) along with the applies on-hit of her new Lunge.
She just doesn't apply damage fast enough anymore to really play the assassin style of speed in, burst down, speed out. She'll need defense to stick around long enough to get the most out of her ult, and as you mentioned - %Max HP true damage negates a lot of need to build damage to deal damage. Which means more bruiser damage, more bruiser defense.
Very similar parallels to in overall kit design now, much more in that direction than 
Why would they changed an ad carry for a tank? Sounds ridiculous isn't it? But still, they did it!
She's definitely more duelist than team-fighter now.
Honestly, i feel like either her base damages will be stupid high and she will be op, or she will be a useless tank that never sees play, or even less then she did before. I can't see her dueling very many of the current duelists and surviving with a kit like that. To even have a purpose in a fight, that healing ult needs to follow her, not the now dead enemy. If that was the case i could see an arguement for playing her botlane as a support. Even so, i feel that may even end up being her destiny atm.
