I've been using Yasuo Lately and i love him, but the thing is my friends are saying he is extremely over powered. For example his windwall I agree with them that it is op because it does block very strong skillshot ults. So how op is Yasuo? 
Completely broken, in low Elo. However, Higher Elo players (Diamond +) can counter him quite well. The counter to Yasuo is AOE damage in team fights (Kennan, Darius, etc), along with CC.
In lane Zed is an excellent pick against Yasuo.
Anyways thats just from my experience by playing him in Diamond + normal games, (I don't play ranked). https://www.youtube.com/watch?v=XfuEH3ic_WE
his windwall is op but the rest of his kit isnt and he has many weaknesses so hes fine
He's garbage at low Elo, so idk why so many people complain about him. Unless you're Master you play with trash Yasuos who probably just happen to counter your favorite champ.
No people on G&B are just retarded low elo scrubs that let him dominate them
In a scale from Not OP to OP I'd say he's OP
ive said it in a few yasuo threads now. yasuo is slightly overtuned imo. he is not OP by any means.
he just has a kit that makes him frustrating to lane against. the more you play against him (which will happen often) you will learn to play against him. if you main him, you already can see his weaknesses.
he has pretty ridiculous mobility, a strong early game, the windwall can heavily outplay you, and his flow is just a bit too much. the windwall i think i am ok with, ive said it a lot but I feel the duration is too long on it, but the function is fine. the flow feels out of place with his theme.
Wind Wall basically gives him two ults, one defensive, one offensive. How can he not be OP.
Frustrating to play against, yes.
Overpowered, no.
He is not OP, he's just fun to play. Sure he can dominate games if you give him kills, but so does every other hard carry. People just seem to underestimate his mobility in trades sliding in and out using minions. If you position properly in lane and control the minion wave he can be managed fairly easily. When I play him I usually manage a kill before level 3 or force a recall and summoners. His level 2 is stronger than about anyone, those who know that use it to gain a lead and never let it go.
In some situations he's extremly op, mostly due windwall. But overall, he's a strong champ, but only slightly op at most. He does have an incredible annoying laneing and splitpush, which is why many people complain about him.
Depends.
In a teamcomp with 
or a similar champion, he is stupidly powerful.
Otherwise, he is just OK.
Against teams who are incredibly reliant on projectiles (
) he will become a living god with his windwall.
Against teams that could not care less about it (
) his W is a dead skill for the entire game.
There are a lot of bad yasou players in low elo, they like to pick him into groups with no synergy and they often stay behind if they get behind.
The only op thing is that he is manaless.
I think he need nerf. i know i am no pro but since he pwns in every single game, that dont really matter. One of my friend have tried him and can't make it work, but all the people i play against snowballs after few minutes and wins the game. One man army. You might just say that i need to counter him, but me nor my team mates cant find out, and the we loose. And no one else needs counter at my level. He is just not fun to play against. I once saw him do a 1 man penta.
So Riot. If you read this. Please nerf him, i dont know exactly what he needs (i am still no pro). but he needs nerf.
