So I think I found my preferred Yasuo item build.
Doran Blade(1 or 2 early) --> Stattik Shiv --> IE --> Merc Treads --> LW --> BotRK --> GA
Runes/Masteries I'm still tweaking with. I am currently using the setup that Tortfeasor posted:
Last night I was carrying a game so damn hard but ended up losing due to a DC. (2nd time losing from DCs with Yasuo in past 2 days. It's ruining my stats! I would have over 50% win rate if not for that).
I decided to browse some streams and ended up watching Vman7 play Yasuo. He was using the same exact items and was carrying all of his games. Definitely affirms that the build works if Diamond 1 players can succeed with it. However, I think Vman is going 21/9/0 with Runes. For now I'm sticking with the 9/21/0.
Are you playing him mid or is this universal? I've been play Yasuo top all day and I typically build him bruiser and not glass cannon. I would build him your way if I was going glass cannon.
I've been playing him D.Shield then D.Blade. Then work into Shiv - Defensive Item - IE ... and play him like a bruiser. Once I get Banshee's veil it's GG.
I also don't see the point of AS marks. It equates to like a 3% CDR on your Q, or two levels worth of AS. It doesn't effect it really imo. I prefer the extra AD for last hitting early. I'm also running a bit of a hybrid mastery build, 17/13/0 so I get that one point into perseverance and it really works well for sustain.
On the way into work today, I was thinking about a different type of build though. If you're against a sustain champ top, build into Executioner's Calling first after a Dorans start. Then build into bork - Defensive item - Shiv.
Then thinking about runes, I'm thinking about running 6 hybrid pene marks, 3 crit marks, armor yellow mr blues then 2ad quints 1crit quint. I have to test it out though.
edit:
What about build paths? I've been experimenting with QEW then E > Q > W. Getting that CD on your E is amazingly good for trades early. I'm going to stop leveling my ult after the first point too I think. It's too unreliable if you don't have knockup comps. As I get better with Yasuo's Q, I'll probably revert back.
Playing Bruiser might make W more important than Q though due to the passive. Your E fills up 20% of your flow just by using it before distance traveled. It essentially makes your E do 27% flow fill up, with a shorter cooldown, you can fill up your shield all day easily at max rank.