She's 100% a top-lane champion now.
Her dueling potential is still pretty solid, and her trades are really scary with
turning her Lunge + slow/crit combo into what's essentially 3 critical strikes in a row. Add some solid 1v1 mind-reading and Riposte makes her really deadly.
Also, with %HP true damage she can pump out some serious hurt vs. wet-noodle top lane picks. They can't just
and ignore her anymore, she can build damages and proceed to actually do damage vs. them.
most teams dont need more damage going top and her scailings are terrible to just go full tank
A lot of teams run a mage top lane. Looking at the defensive item nerfs, a lot of teams in worlds will probably go for more of a damage-heavy top over sending a tank up there.
You don't have to send a tank top.
And Fiora will still have some durability looking at her kit. It's a lot like that of
Solid damage potential, but you really can't use it without building some defensive items. With a decent offtank in jungle or with a tanky support, you'll have enough beef for a front-line with Fiora sending her top isn't a huge issue, especially seeing how solid the tanky supports are now.
I've generally found 1 committed CC tank or 2 fighters will often give you the front line you need, and there are plenty of places to fit some tankyness.
Also on tankyness - the options aren't simply glass-cannon or full tank, you can mix both together, which is exactly what Fiora needs to do ATM.