Would Full Crit Fiora Work?

No. Fiora q cannot crit, she does not auto during w, her first e cannot crt, her second e will always crit making crit chance irrelevant, by the time you have finished uwing w and her two e autos her q is up again which will always be needed to keep chasing and repositioning especially because her ult makes it more important for you to hit vitals than anything else. She's also a melee champion with no defensive scalings (adding resists and hps to your invulnerability tool doesn't add anything) so she needs to build at least some tank items to survive in range of enemy damage long enough to get her ult off.

All in all crit chance and damage is almost 100% useless and inefficient on fiora.

She'd be squishy as all fuck.

The big thing is you still want to get some heavy sustain, but I think IE and a Shiv would work well on her.

Fiora's Q can not crit. Also, her E stops her from critting on the first attack. I'd suggest sticking to the normal build, although I suppose throwing in a couldn't hurt.

im actually a pretty big fan of PD on fiora. i love the ms/none minion block then the attack speed and dmg reduction.

i def dont build it core but if im ahead and the enemy in lane will become harder to deal with, instead of defensive or if im just feeling frisky ill build pd

Hydra, Cleaver, DeathD. is your core. Maw, Visage, Rands, Plate, Scimitar are situational Bloodthirster as 4th item if you are snowballing. Sustain>Crits on Fiora. I play her a lot.