I doubt that Yasuo will be nerfed, because I think that Crit itemization is probably gonna be nerfed. There was a price increase to Infinity Edge that was on the PBE a while back, and while it was never pushed to live, it does seem to indicate that Riot is trying to maybe tone down the two item powerspike you can get with Shiv/Infinity Edge.
So, if Riot is planning to nerf Yasuo's core items, I imagine that they'll wait to see what sort of effect that will have on his power before actually hitting him directly.
I personally think that Yasuo is on the upper bounds of balanced at the moment, and people are still banning him because A) He was nerfed very gradually, so there was never a patch with the narrative of "oh, Yasuo's bad now" like there was for Soraka/Kayle, and B) Because everyone remembers that one game where the enemy Yasuo hard carried and they still have emotional scars.