Fun fact... 10% less damage on crits is still a LOT of bonus damage. Hell, let's say his crits do 180% damage instead of 200%. A 20% loss. Let's also say to keep our math easy that Yasuo has EXACTLY 100 AD. (He'd have more after getting two items and hitting 100% crit chance, but meh. It's just an example) Ok, so Yasuo flies at you to trade because you have dared to stand near your minions (if you're melee and don't want to lose farm, this is inevitable).
Yas dashes into you doing his piddly dash damage, then autos you. Crit. 180 damage + his static shiv proc (because let's be honest, he rushed shiv) doing an extra 50-120 damage... which ALSO crits. So let's say it does 50, the MINIMUM. So with his crit reduction in damage, that's only 90 damage more from the shiv crit. He then mashes Q to reset his AA, landing another crit instantly for another 180 + the damage bonus on his Q (which I can't recall off the top of my head). In the span of a half-second, he's done 360+ physical damage and 90 magic damage. WITHOUT the doubled crit he'd have done 250. You talk like the -10% crit damage is a HUGE deal, but even with that he's STILL got a passive that gives him 80-90% more damage on his autos on EVERY attack once he hits his second item. (Fun fact, most games are decided in midgame when everyone has 2 or 3 items).
This is a thing I see from Yas players a LOT. "But there's a downside to it!". "If I use wind wall it's on a REALLY long cooldown!". "If I dash in without enough minions I can't dash out!". "Sure I crit every time, but for 10% less damage!". No, you crit on EVERY hit for 80% MORE damage. Your wind wall is a basic ability that nullifies ranged spells, ults and auto attacks. Your dash gives you nearly limitless mobility and zones the enemy from CS in lane. Your shield gives you a refreshing pool of bonus HP and you don't need to do ANYTHING to use it properly. Your ult is a massive CC nuke that also removes most of the armor anyone you hit with it has bought. Yas can kill tanks, carries, assassins, bruisers and mages, hit kit has the tools in it to outplay and slaughter ANYONE... it's just difficult to use to 100% effectiveness.
That doesn't make him balanced! "But... I don't do the damage of a lategame adc" isn't a flaw. It's a trait that EVERY CHAMPION IN THE GAME has who isn't a lategame adc! He's a melee fighter! What's more, lategame Yasuo WILL destroy a lategame adc in roughly two hits... Said carry however will probably not be able to do the same thru Yas' shield, wind wall and the fact that Yas probably built semi-tanky after getting his 100% crit. The fact that he can even come CLOSE to the damage of an endgame carry is a massive bonus in his favor.
Yas players complaining about his kit or talking about his "weaknesses" reminds me of someone winning the lottery, getting 14 million dollars and then complaining that it COULD have been 15 million. It's some kinda weird, self-entitled thing where they think that he SHOULD be able to spam wind wall every 2 seconds, dash without minions there and ignore ALL of a tank's armor instead of only 70%. "I'm Yasuo, I should be able to hit 100% crit off ONE item, but I can't so it's balanced.". Not many other champs in the game can do the same absurd crap that Yasuo can and the ones who can are usually HIDEOUSLY OP. The ONLY weakness to Yasuo is how easy he is to misplay with. So please Yas players, stop griping about Yasuo and how he's weak at this or not godly at that. Not everyone is amazing at everything and has a kit with an answer to anything and everything. Not everyone gets a mountain of free stats, snowballs absurdly hard, scales extremely hard and can still wombo to win a teamfight from behind. Not every champ can go 0/5 in lane and still be a threat once they finally stumble into their second item. These are not weaknesses, these are strengths. Your champion is ABSURDLY strong. You're just not good enough to use him right.