He IS weak to ganks. His dashes can't take him to his side of the map unless you've pushed the wave to him. If it's by your tower, the farthest he can go is the middle. He is forced to push the wave to charge his tornado or to dash. Focus on harassing him, and the wave will come to you.
Everything Yasuo does is telegraphed. You know when he has his shield, you know when he has his tornado, and his dashes go a fixed distance. His Windwall is one of the longest cooldowns in the game, longer than any one spell you'd use to bait it out. Threaten him with CC, force the Windwall, then back up and try again when Windwall is still down.
His tornado is a relatively slow projectile with a cast time. If you sidestep it, he will not only have no CC or ranged poke, but also no ult.
Yasuo is a skill check champion that tests your ability to avoid a telegraphed skillshot, manage the wave, and take good trades with your opponent when their defenses are down. If you fail the test, Yasuo stomps you. The idea that Yasuo is this unbeatable broken monster is only really present in NA. He's actually more popular on the Asian server, and he isn't hated or feared over there. He's considered a fair and balanced champion, and his winrates across all regions prove it.
