omg...
First of all, this is assuming you and JG are sticking together on killing him. I thought that was obvious enough.
Second of all, Playing someone like Lux, Leblanc, or Kat, it should be easy (at least for me) to wittle him down with pokes or maybe just bait out his windwall so you can hit him with brute force...
Third of all, you threw Jack at me at the last sentence. Duelist whatever, doesn't matter. It's whether you can handle him or not, he negates your entire kit and/or he's a god. And I don't think you understand that it's not just him being behind that makes it "easy" to fight him. It's whether you have common sense on if you CAN WALK AROUND THE WALL, and keep a distance away from Yasuo at the same time. Someone like Zed can just put a W through the wall and poke him. If you had common sense to walk around a wall, then you have common sense to avoid a Yasuo Q. Seriously, it's really not that hard to dodge if you know how to make him miss. Buy QSS if youre tired of his ult, use it right when the 3rd Q hits. If he ults you fast enough and you dont use QSS, use QSS while in the air and flash away (if you have flash) to avoid the damage from the ult. He will only have his bonus armor Pen from there on so nothing should be super wrong when that happens anyway.
But yeah, he's a good duelist. It's not his fault he's good at fighting.