The only way they would do that is if they reduce not only Q damage but his solider damage and remove the shield completely as well, cause his Q damage was not the problem. The problem was you couldnt avoid his damage if he hits his knock up. Because once your knock up he gets a free ult which does half a squishy hp and then 2 aa and maybe another Q and most champion would prob be dead already. Theres no counter play when he has that knock up, now he can only use as peel and not as an engage and use the insec play only if he has flash.
Not only that, Azir did everything. Burst damage, sustain damage, slow, knock up, knock back, shield, mobility, zoning, a wall that no one can pass through, attackspeed, and a free turret. Be happy they only took one away, cause if they give him back the knock up, than burst damage or sustain damage or mobility has to go. And trust me, if they take away any of those 3, Azir wouldnt be played as much anymore. The knock up removal is the least they could have done to him which makes him still super strrong late game with his peel and zoning potential while still having him tanky with shield. Not to mention they didnt even touch his damage output.