*Fact: A champion has the ability to use the activatable item Zhonya's Hourglass during the animation / physical knockup of Yasuo's ultimate.*
Evidenced here (as well as in the DIG vs LMQ game):
So before we delve into the mechanics of this, let's take a look at what Yasuo's ult actually does:
>Yasuo blinks to the nearest visible Airborne enemy champion to the cursor, instantly generating maximum Flow. Upon arriving, he suspends all airborne units within a 400-radius of his target in the air for 1 second while dealing physical damage to all of them.
So how does Zhonya's play a role in this?
If we look at the above YouTube video again, we can clearly see that the champion on the receiving end of the ultimate acquires no damage at all due to the Zhonyas immediately taking effect and keeping the target protected from the brunt of the damage.
Calling upon the wonderful wiki again:
>Hard CC — The following effects completely remove control of one's character:
So if "Hard CC" removes a player's complete control of the champion, why can the player still use Zhonya's to opt out of the Hard CC if items with actives and unable to be used while the full duration of the Hard CC is happening?
I believe strongly that this is a bug, and that it needs a remedy (hopefully soon). It already has a very real impact on current gameplay, especially competitive gameplay (the DIG vs LMQ game specifically), by inhibiting the ability of a team to follow up on the Hard CC lockdown of Yasuo's ultimate.
EDIT: Talking to Daen on via client, and he linked me to this thread:
Within this thread, Rioter "CertainlyT" shares some insight on this *bug* (he specifically classifies it as such in the thread)
>This is a bug that can sometimes occur when one CC replaces another. It should hopefully be fixed for Yasuo's R specifically next patch and all champions by the patch after.
But this response was posted 12/23/2013... so where exactly did the fix go? As this is a critical gameplay influencing bug, shouldn't it have been corrected before competitive play of Season 4 began?
In any case (don't want to point any fingers at Riot, just looking for a solid fix on a live gameplay issue), here are some of my recommendations:
a) Remake the DIG vs LMQ game to address this specific issue, if this issue is ruled as a bug (possibly disable Yasuo until a hotfix can be made)
b) Whether this is ruled as a bug or not, please clarify (through forums/wiki) whether Zhonya's has the ability to cancel hard CC abilities, specifically airborne ones.
c) If it is a bug, please notify the community about the existence of it, and disable the use of Yasuo in competitive play until a fix is made.
If anyone has some better suggestions for a way to resolve this, please let me know in the comments.
Thank you for taking the time to read this, and have a lovely day!