Personally after playing yasuo extensively for the past few days, I feel at the moment Yasuo's best moments are mid game before people have full builds.
When everyone else has full builds Yasuo feels like he is lack luster.
If he is just built straight glass cannon he seems to drop off as he is too squishy for proper melee combat even with his passive and Wind wall utility.
My instincts seem to tell me the most optimal build for him will probably be an offensive heavy bruiser build that can stand a heavy beating and still deal moderate damage.
Feel free to share your thoughts as well.