oh boy you rly want that ?
playing yasuo made me a realy good sivir player (mechanicaly ... at least i think so when i look at the stuff i block)
if you will make his w sometthing like a skillshot that sweeps projectiles away (fits thematicaly, it was supposed to resemble cutthing the bullets but they wanted him to help his team more instead of being selfish) then you realy buff him to the point where he incapacitates any skillshort relaint mages (they usualy rely on one skillshot like ahris E, and playing yasuo realy sharpens your reflex ... even to a point where you will block any charm even at point blank range, im afraid of that)
and you force them to drop the cooldown down
i would like the change, but you propose a buff not a nerf (just to clarify, you will make yasuo better at removing important projectiles , so a lot of work needs to be done to ballance that)
I personaly find yasuos item synergy the most problematic part in his kit (wind wall has low counterplay, but its the item synergy that makes him bounce beetwen being op or up without any middle ground where he is ballanced)
when he gets ie and static he pays 6300 gold but gains additional 2250 of stats which then synergizes with any ad and lifesteal he gets even harder ... its safe to assume that yasuo gets 2x the stats he pays for
so if yasuo is allowed to lane on par with other ppl (i mean a ballanced lane where yasuo doesnt get wrecked like on live, and doesnt bully too hard with bare stats) he sill straight out dominate once he gets items just because he gets more stats (yasuo itnt realy a hypercarry who has some insane magical power late game, he scales hard but not what i would call a meele hypercarry, the squishyness gates his power good) so he snowballs out of nothing and easily outpowers his enemy , meaning in more snowball and more items
This makes yasuo who isnt insanely powerfull, insanely dominant. He progresses through the game twice as fast as others (you start getting crit while yasuo crits every 2 autos, you got your 45% crit yasuo has 90, then it translatess to him powning harder than you ) . so in mid game you will face yasuo with late game power level, he will punish you till the end game where he will still hit hard but wont be so owerwhelming (hell be focusable. ofc assuming he has no malphite, his squishines will have some exploits but thats where your windwall change steps in)
thats also why the hp nerf proven to be so effective on him, it makes his early trades worse because he can get blown up without dealing enough damage (he is a sustained damage dealer so he is suspectible to burst, guys like Yasuo are usualy tankier to compensate for not being ablte to drop ppl so fast as syndra, he just lost that)
when it comes to counterplay your change is nice but it does not solve the innate problems of his kit straight out, if the cd will be adjusted to allow him for a lot of early blocking then he will be a free food for anyone who isnt 100% projectiles
Let me summarize my thoughts.
-Your change is nice but Yasuo needs a loads of work to actualy fix him, giving him counter play is just a parf of what needs to be done.
-Yasuo's scallings dont realy allow him to be touched in any way besides a kit tweak or a rework on some parts, any buff will cause him to blow up and get back to prenerf state.
-Your change is both adding counterplay and removing some (wind wall is not a free tool for his team/ but its easier to swoop projectiles from mages hands) while also causing some problems (mages who dont rely on projectiles will hurt yasuo harder than they should, since he cant just put up this wall for a sure block on whatever projectile they throw during non projectile based combo)
but both problems might be tampered with by some tweaks (hell always be on the weak side with non projectile stuff, but you might give him better tools to survive ranged harras overall while hurting his mage blocking potential in teamfights, this way he gets to be on a more equal footing vs both where he will just block early harras )
