I like the changes to Azir's W, it gives him the ability to place new soldiers after chasing or running more quickly, and does not give him a ton of power. Though I really dislike the idea of buffing his passive as a means of making him balanced. I mean yeah itd be nice if his passive was slightly stronger, but I feel that I dont play azir because of his passive, I play azir because of his ability to auto attack as a mage from a distance and have small windows of burst and mobility. His ult seems very underpowered now and I know you recently nerfed it hard and his early damage. I would much rather see his passive changed or something and put the tower making onto another more thematic champion. Its really just another extra that he has that fits a little but not amazing. Please dont use too much of his available power into his current passive though. I would say, if his ult is only gonna last 3-5 seconds instead of 10, then make it wider at all ranks to compensate, this would simply make it easier to hit and hit more targets, since it wont keep them out, and this makes him slightly easier to play, further separating the gap from LCS to normal people.
If Azir existed with a knockup on his E, a shield on his E, a wall that lasted twice as long, a second passive that gives him free Attack Speed with CDR, a W passive that lets him smite towers, more base damages early, a passive that lets him summon a pseudo tower, and a lot of small other things, then I'm sure he can exist with a few of those things, maybe even replace his tower passive with the CDR to attack speed passive. Overall give him power where he is thematically fun, not where it works to give power to just because it doesnt help pros.
As a side note, now that his E doesnt knock up, having it stop on enemy hit is no longer a good thing, and usually only a bad thing for Azir (it was truly a double nerf). Maybe make his E go through champions and apply the shield if it goes through one. This is also another source of power that helps his escapes and positioning for knockbacks potentially, since his knockback is very limited as good peel now.