Yasuo isn't my go to ban, those are Zac and Fiora, mainly whichever one my team doesn't ban since everyone generally permabans Fiora, but if somehow both get banned before I get my choice, I ban Yasuo.
Zac is stupid strong in single handedly winning a game due to literally how much he can do. Fiora is broken and Riot won't nerf her, when even high elo players and even some pros think she is dumb.
For me I ban Yasuo since I simply don't like dealing with him. He isn't hard to lane against, but I don't like that no matter what I do he will become Yasuo and be a threat. I don't like the idea that literally anything I do to him is 100% worthless since he will still become Yasuo when he gets IE and Phantom Dancer. It isn't fun to be playing as, or playing against a Yasuo that is 0/10 which is a meme at this point since most Yasuos literally do get scores like that, but they can duel and possibly even beat your fed people since he got 2 items. I've played Yasuo myself and I generally play mega passive and its sad that as soon as I get to that dream point, I can basically fight anyone easily, its like....sad.
At least champs like Vayne, Jax, and other monster hypercarrys if you set them behind hard enough early, they stay behind for a while if not for the entire game. Yasuo the only way to keep him from it is by literally keeping him grey screened the entire game.