What is the counterplay to Yasuo?
Counter-play is mostly just the number of responses to this question:
"What could I have done differently to prevent that from happneing?" After a Yasou kills you.
In which case you do have plenty of things to do.
Vs. Q you can list lazily to the left. Dodgy movements as a melee or range, and simply walking through him as a melee, will often prevent him from landing the skill.
Vs. W not standing next to your own minions prevents him from using it to reach you, and more importantly to bail if the situation doesn't go in his favor.
Vs. E - you can walk through and around it, bait it out, and hold back on skills to not get obliterated by it.
Vs. R - dodge to the side vs. his tornado, or apply mobility-silencing CC on him if the tornado looks like it's inevitably going to hit, as doing so will often disable his ultimate while airborne CC is applied on your character.
Vs. his passive - 1 mana potion can generally allow enough skill use to get past the HP shield on anyone with decent ranged harass. On anyone that's melee - you should be able to Crush Yasou in a straight-up 1v1. Double crit is useless with 0% crit chance, and his HP shield is mostly good at staving off occasional poke, nothing amazing in a fight to the death.
Vs. his AA's - those are melee range. Anything beyond being a potato allows you to play around melee AA's.