Yasuos windfall now has a dmg threshold based on flow
When Yasuo activates Windwall it consumes his Flow and blocks projectiles up to X damage based on how much flow he had built up. With zero flow it still has a minimum value. To compensate a little his passive shield can be buffed.
Now he can't face tank an ability or auto then Windwall the rest.
Blocking an ult sucks enough for the enemy but blocking that plus a bunch of abilities and autos is just stupid (more of a problem in low elo but still relavent in all)
It makes thematic sense that he's building up this flow and releases it into a wall
Sounds reasonable to me. He can still out play and block that Ashe arrow and still has his defensive abilities to handle a ranged vs melee lane. But he can just laugh at a barrage of abilities and auto attacks.