Something ironic about Fiora's rework
is considered to be the best counter to the current Fiora.
Jax can outduel her, he can dodge her auto-attacks and even Blade Waltz using Counterstrike, his Grandmaster's Might active part can give enough armor to whitstand Fiora's damage, and he can then burst her down.
However, when I started to look at Fiora's new kit on PBE, I came to an ironic conclusion that the new Fiora will actually be a counter to Jax.
The new Fiora will use her Riposte to avoid being stunned by Jax' Counterstrike, and will actually stun Jax himself (she must predict it well, though, since Jax can activate it early). Also, her passive will bypass the resistances given by Grandmaster's Might. Then she can use Grand Challenge to deal a great portion of Jax's health in damage and heal herself, out-trading him.
I predict that other formely hard counters to Fiora, such as
, will no longer be counters to Fiora, at least not outside of the lane phase. In Pantheon's situation, he currently can harass Fiora out of lane, and out-trade her with his passive, bursting her down. He can also affort to build tankier and will outtrade Fiora at every stage of the game. However, with the rework, Pantheon will be unable to stun Fiora because she will just use Riposte. He can still win early by outharassing her, but Pantheon will lose late game seeing how Fiora can't be stunned and she can use her ult to out-trade Panth.
Also, the current Fiora is hard countered by tanks, as they can just stack a lot of armor and out-trade Fiora with their high base damage, since Fiora is squishy. Indeed, Thornmail is an item that hard counters the current Fiora, it can even reflect the damage from her ultimate. However, the new Fiora may not be as weak to tanks, I wouldn't be surprised if she turn out to be **good **against tanks, due to her passive and ability to negate their possible CC's (attack speed slows, stuns, knockups, etc).
Of course, all that I have just written is just a bunch of ideas, theories, things that I am not sure that will correspond to the truth until her new rework is actually released on live.