Zhonyas should be usable under cc...

because the whole point of QSS is to remove cc?

Zhonya's should be used pre-emptively to outplay CC (or agro), not to cheapen CC duration. Take if you want to get out of CC

So you're basically saying that you want to say goodbye to counter play. Uuuuuh... lul?

QSS can do it...

https://imgur.com/vPGT6be

None of those are actual reasons for Zhonya's to invalidate CC.

The general rule of thumb is that AP items have actives that require quick reflexes, planning, and can be locked out by cc.

AD items require absolutely none of those things.

"Hey guys, let's take one of the most powerful item actives in the game, and make it even more powerful."