You're proving his point exactly... Yasuo limits the viable champion pool just by existing.
What if Yasuo + enemy mid hasn't been picked yet, and he wasn't banned? Whelp, half of the mid laners I could have played are at risk of getting Yasuo'd.
Having counters is a TERRIBLE argument as to why a champion is or isn't balanced. It doesn't matter that I can wreck Yasuo with Jax or Riven if I've already locked in Twisted Fate or Ahri.
Look at their kits instead.
E.g. comparing Yasuo to Ahri (a champion that's long been considered strong and has received nothing but nerfs since 5.2):
- Yasuo has no mana problems, Ahri does
- Yasuo's CC can hit multiple targets
- Yasuo's CC is much easier to land on its own (passes through minions rather than blocked by them)
Dropping Ahri's charm and Yasuo's whirlwind, since it's already established that the whirlwind is strong...
- Yasuo has better sustained damage, and can take down towers more easily
- Yasuo is arguably more mobile, his dashes require a target but aren't on his ultimate
- Yasuo gets free stats via double crit
- Yasuo has stronger burst with his ultimate
- Yasuo's wind wall can block so many attacks and abilities, save turrets, and if used properly can deny the enemy adc from doing any damage in a teamfight
- Yasuo's shield is arguably equal to Ahri's healing on her passive
- Yasuo is tankier and has better base stats and base MS
- Yasuo counters almost every non-melee mid laner (except Malzahar, Azir, and Lissandra as far as I can tell).
In compensation:
- Ahri can attack from range
- Ahri is better at kiting
- Ahri can combo her ult / flash with her E (except Yasuo can also combo his dash / flash with his whirlwind so...)
Yet it's Ahri that receives so much attention for being OP rather than Yasuo. Why? Because her flash/ult + E combo isn't as predictable? Because Yasuo is more team reliant and hence doesn't work as well in solo queue? Because solo queue Yasuo's end up with all AD teams? Because Yasuo's flashy plays are more attractive to 'bad' players that bring down his win rate?
None of those are valid arguments - they're player decisions and have nothing to do with balance.
I just think it's time that Yasuo loses his double crit passive. Put more strength in to his kit elsewhere if necessary. With all the extra crit items in the game, he doesn't need that passive anymore. Even without the new warlords bloodlust mastery, he's unhealthy. Not to mention almost every new champion having a knockup since his release has given him a lot better chance of having help to set up his ultimate...
And after saying all of that, while I still thought Yasuo's kit was overloaded I was okay with him because you could take out his shield with an appropriate auto attack then engage while it was down and he had no means of regenerating in the early game. I've won the Ahri v Yasuo matchup a multitude of times. With the new masteries though, he's over the top...