Yasuos only weakness is the fact that he has no weakness.
It gives the player a false sense of godliness that baits them into repeatedly 1v5ing.
Fortunately enough for the Yasuo player, Yasuo is so broken, that this type of suicidal, bronze behavior,actually wins games in the end. Even if he goes 0-10 in the first 20mins.
Because the balance team knows what theyre doing.