Azir's passive just sucks.
It lasts for what, 1 minute? If it never shoots anything and never comes into contact with minions. What is the point of placing a tower that has less bulk than the scuttle crab. No one is going to dive you under the tower at like level 6, and even if they did, they're probably so fed from taking a tower by 7 minutes that they could just kill you anyway.
On the other side of the spectrum, towers aren't usually going to be taken early- which is the only time towers are a threat. His passive is just completely useless.
Either make the tower last longer, Make it tankier towards champion attacks Or make it an inhibitor turret with the laser beam.