Unpopular Opinion: Yasuo is not a problem because he's Yasuo.

Yes, he's frustrating as shit to deal with, and Yasuo mains are the type of people I never want to have to lane against, but from what I see what's really tipped him over the edge to the point where a Champion with a designed-weak early game can shrug it off is not really his fault.

Cutting right to the point, what's making Yasuo such an obnoxious pain is a combination of Mastery and Item changes that have been plaguing the game for a while, rather than his base kit.

not only offers Yasuo the best possible stats for his kit on a single item (given that AS and Crit are things that he wants very, very much) but also grants him 12% damage reduction on the last person hit for a while.

In a solo lane, that's effectively a permanent 12% damage reduction buff.

Then you have . If you were to ask me, this shit shouldnt be in the game at all. I can't think of any cases where a Champion needs to build it because they're balanced around it being built every game/require it to function (see: with and respectively), and because it works off AA's rather than spells with CD's, you end up with a gameplay interaction that involves never being able to escape Yasuo (and anyone else that builds Frozen Mallet), or finding it very difficult to catch him(even without his many dashes).

On the Mastery's side, you have Warlords Bloodlust and Fervor, which respectively grant him free Lifesteal and AD. The Lifesteal makes him harder to push out of lane than he should be (as lack of inherent sustain other than his P - shield is intentional), and the AD can allow any Yasuo with a keyboard and two fingers to poke you out of lane as early as level 2.

Basically, what I'm saying is that as stupid as Yasuo is, Keystones and some of the items/item changes recently are even stupider, and are the main reason he's been a recent point of contention within the community.

That's my two pence anyway.