Yasuo is not in need of buffs, but of his long-awaited rework.
"Our Belief is that if we want to get him into a state where he is both viable and also not a must-ban, we need to tweak more than numbers" - Ask Riot: Yasuo gets banned
So we all know the most hated champion in the game BY FAR, the one that is almost permabanned in low elo and about 40-50% last season in high elo, the one that brings hate towards CertainlyT to this day (along with Kalista and Zoe), is getting a GIGANTIC buff of increased damage on his Q, increased magic resistance growth, and increased ultimate range.
I honestly don't think Yasuo needs to be touched. He may be of below average strength right now, but Riot has not touched champions in a MUCH.WORSE. state and left them in the gutter for a long time. The most notorious example is Volibear, followed by less subtle examples like Skarner, Viktor and Aurelion Sol. They have a lower win rate right now (check na.op.gg), and yet none of THESE guys are getting attention simply because Yasuo has a larger playerbase - clear examples of Riot's favoritism.
Also, Yasuo's kit is considered the most toxic in the game, as he can block literal ultimates with a basic ability and feels really, REALLY frustrating to play against. He isn't broken, but he sucks the fun out of the game from anyone playing against him. I don't think it's that much of a stretch to keep him weak for these two reasons.
But let's give Riot the benefit of the doubt and hypothetically say he needs buffs. This goes against Riot's beliefs of Yasuo and the quote I mentioned above. Yasuo is really strong and frustrating in low elo, but he evidently struggles in higher elo and is rarely used in pro play. This is by definition very toxic.
Then Riot stated that he would be getting a gameplay update to make him better in high elo while making him fairer to play against, in about May this year. This was delayed considerably because of whatever reasons. However, with Yasuo being weak, this is the PERFECT chance for Riot to give this hated champion his needed rework. Simply strengthening him will get him EVEN MORE BANNED and hated, which is exactly what Riot DOESN'T want to happen, and what the players don't want to face. Seeing how Yasuo is 'weak' right now, this can provide very good incentive for Riot to rework him and make him less toxic and more fun to play against.
I highly urge Riot to reconsider the Yasuo buffs, and use this as an opportunity for the long-awaited Yasuo rework instead.