In Your Opinion, what kind of problems does Yasuo face right now?
It seems like no matter what ELO you're in, it is almost impossible to find a good Yasuo that does consistently well in every one of his games if you look at his match history. He's extremely team-reliant and if your team is behind, he is nothing but underwhelming in a teamfight unless he can get a good ult off multiple people or the ADC. Even in diamond, you will see people feed with him all the time and even if he's 3-0 early game, it is not uncommon for him to end up with a score with something like 6-7 in the midgame because of how prone he is to CC and gets bursted down in 2 seconds with focus.
Yasuo cannot carry games by himself anymore like he used to. He probably takes more skill to completely master than any other champion after the long string of nerfs. It's almost impossible to balance a champion that has a double crit chance as the innate passive.
Currently, it's even a challenge for him to survive the early game since almost every top and mid out-trades him with a few exceptions of his counters. And if he's ahead, he is an easy prey for the enemy jungler and laner once he takes a single step out of his safe zone. The only way for him to survive long enough to do significant damage is to build bruiser but then he lacks carry potential and turns into a utility machine.