Ive been banning teemo every match
( i never had to face him but just imagined the horror!)
So I was trying all sorts of Yasuo builds last night.
3-4 games I went Vamp scepter first. It was pretty meh.
I tried all AS runes (about 29% AS) and it doesn't do much at all at the start of the game. Your Q is reduced to 4.1s at level 1. The loss of armor/mr/ad was pretty meh.
I tried a few other combinations and I have to say the best builds are full AD/armor/mr or LS/ad/armor/mr. Until Riot changes some things with crit and crit damage runes (they eluded to something where they actually might); a standard ADC rune set is the perfect fit imo.
Builds: Full 21/9/0 builds work just fine but you're a bit more squishy. I have yet to try a 9/21 build. I will tonight.
I feeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeed last night. I went up against a Teemo that got two kills on me right away. First one was on an invasion where I got smacked by Jax on our Red and I died. Then Jax camped top lane and that was it with Teemo. If I had enough burst I could of killed him, but he was too far ahead and Yasuo sucks at coming from behind unless you have good jungle support.
I tried executioner's calling against Mundo last night. Kind of works and I should of gone 3-0 in lane but I didn't have enough damage.
Conclusion: For me anyway, you have to rush Shiv because you get such a huge power spike with it. Getting anything else is bad as a first item. Second item depends on the game. If you're ahead of even, IE. If you are behind or think you might be behind soon, Banshee's veil is so OP with him. That spell shield synergizes with him so fucking well. Especially mid game.
I also concluded that leveling your E before your Q is most likely a mistake. Getting that cooldown reduced on Q is so essential. Each AS rune reduces it by 1% and each Quint is about 2%. So stacking those is almost useless.
As a third offensive item after SS/IE, I think Bloodthirtster is better than BORK. Need more testing though.
edit-
Third conclusion. FUCK TEEMO. Gonna see more of him because The Rain Man has been playing him for a week straight and nothing else top lane.