Yasuo honestly is pretty good in all stages of the game but does have one huge weakness in that he is squishy as hell. If you can lock him down he is pretty much toast. or even then. if you focus him quickly when he jumps in he is also toast.
I mean in the c9 vs fnc game where balls got penta. yasuo went in, and immediately got exploded because of how squishy he is even with a dead man's plate at that point which is not typical on yasuo.
what makes yasuo annoying is his oppressive lane phase and how fast he snowballs due to his double crit chance. he only needs one item to spike hard and two to spike insanely. 3 and hes basically full power and can build whatever the fuck he wants after that. his lane phase has been hard to punish for a long time because of his really good mobility, windwall, and his flow. its like when his windwall his down. his flow is up. very very frustrating. I won't go so far to say he's overpowered because honestly I've played as Yasuo as well and his skill cap is pretty high. but he is definitely un-fun to play against as the majority of the time he can just constantly push in your wave and he has two tools to defend himself in his windwall/flow. Melee champs struggle cuz the flow and ranged struggle cuz of windwall.
personally I've said it for awhile now the only thing yasuo needs is the windwall duration to not last as long. thats it. currently he can just throw it out for an entire duration forcing you to go around it or even deny you creeps for a decent amount of time. I don't mind how the mechanic works, it is a core part of who yasuo is, but i wish it was more skill reliant rather than "im going to throw this out and zone you from whatever you want to do for 5 seconds or so". or however long it is. it feels like ages though. If it required him to time the skill shot coming at him or projectile it would feel more like you got outplayed.
his flow feels kind of annoying too as it doesn't really seem to fit him thematically at all. like they want you to walk around and be a wanderer just like he is in his lore...i get that. but it doesnt seem like enough. it gives him a shield basically that honestly is not to be understated as it protects him in short trades quite well. I feel with all his mobility already he doesn't really need the flow at all. its kind of like a weird mini banshees almost (not quite as it wont block CC but you get my point). Double crit, wind wall, and endless mobility within an area with lots of targets is enough. he also has pretty decent movement speed with his base movement and how he builds shiv, triforce on top of his boots.
TLDR= don't feel yasuo is OP, but his flow doesn't fit with his kit thematically and makes it frustrating to try to punish him as well as his wind wall duration just lasts too long.