It's 4 years old but it's still gold: https://boards.na.leagueoflegends.com/en/c/gameplay-balance/lBkYPFEW-as-a-plat-1-yasuo-main-with-400-yasuo-games-yasuo-needs-a-damn-rework
"His Windwall should drain his FLOW. Allow it to completely eat the first non-minion projectile, give it a small amount of base health, and allow it to have scaling health based off how much Flow Yasuo has. It doesn’t make sense that Yasuo has to generate his flow to cast his passive shield, but suddenly whips a ton of wind out of his ass-cheeks to cast an indestructible wall of flatulence. Combined with his original Windwall passive, leveling this ability gives him a stronger wall because he generates flow quicker."