Lets Fix Something, Together (PS Trigger warning for Yasuo Mains)
Yasuo is a little too curb stompy when ahead in lane and has a pretty well defined role(s)
However, the issue may be not in his wind wall or damage in general, maybe its the ease of which he can wave clear and look for opportunities to get in to get your guaranteed first blood in the lane, What I propose is a change to his Q which will punish him (Like many mages are) for shooting his 3rd Q down through minions and having to be safe about play, when he is meant to be a high risk high reward.
My change is as proposed, simply just
On the third Q Yasuo's Whirlwind loses 6%, 5.5%, 5%, 4%, 3.5% (Per point in Q) damage per each enemy unit the whirlwind knocks up.
If he is tested and he lacks damage this way, you could incentivise the player for risking his flow shield by giving him a damage boost cutting the damage reduction per each enemy hit the whirlwind knocks up in half, since he is already either being poked or is currently in battle.
Don't Cry Yasuo Mains
[sg-ahri-2]