Holy crap...Azir's damage to towers with his w is insane. At level 5, the base damage it does to towers is 440, and that's without accounting the high ap ratio. On top of that, when Azir gets nashers, he takes down towers even faster. In league of legends, AP mages are generally suppose to have powerful spells, and weak AAs. Azir should not be an exception. Azir IS an ap mage, so why he he capable of shredding towers as fast as an adc?
I know the change on his w to do instant damage to towers is so that Azir can't just hit enemy towers for free with his soldiers. But I don't think giving Azir the ability to NUKE towers is the right approach. I think the damage to towers part is alright though.
So my suggestion is to keep the "instant damage" part the same, but nerf the damage...a lot. To compensate, it would be nice if Azir's w kind of grants an ohmwreaker effect. Like, maybe when you cast his w, it can do damage to tower, and stun the tower for 1 second. I think with this, Azir would maintain a weakness of ap mages (the incapability of taking towers fast). Also, there can be more plays to be made around his w. Like maybe you can save a teammate's life by disabling the last tower shot which would have killed your teammate.
Anyways that's my suggestion, what do you guys think?