im going to be 100% honest here.
Yasuo is obnoxious because Yasuo is one of the first if not the ONLY champions that has both a kit and look that completely fulfills the theme of what was intended with the character. so he doesnt suffer from identity crisis like most champs on the rift.
if he's overpowered or however you want to put it it's because unlike champions like jayce or tryndamere his kit is intuitive and makes you feel like you can do exactly what a samurai would be able to do.
yasuo's critical strike?
it's meant to show the precision of yasuo as a samurai. i've never once seen a show with a samurai where the guy holding the sword wasnt performing fatal slashes with 1 or 2 swipes.
yasuo's windwall?
https://www.youtube.com/watch?v=Qzhs1Z8Rwnk
yasuo's dash?
is a cliche for anime samurai and samurai movies. it tends to be followed by a draw attack - which is the same case with yasuo. often ending in two samurai silhouetted screen where one (usually the victor) staggers slightly and then the loser falls. i KNOW you've seen this many times.
yasuo's passive spell shield?
is meant to imitate the ability of a samurai to move faster than sight to parry or block any attack in the first moments of battle.
yasuo's R?
it's supposed to be a super attack like any samurai would do where they overcome their opponent and end them in consecutive swift blows. anime does this with non samurai characters.
yasuo's Q is a thrust attack to combo into his slashes. which is very intuitive