Azir's ok, kind of
Let me start off by saying Azir is probably fine, maybe a little on the weak side, but over all ok. That being said, I feel like he has some problems with his over all game play.
To me, his largest weakness is he only has one skill to trade with in lane, his Q. Which, more often than not, puts you in danger to use because of its relatively short range. This is a problem because if Q misses for whatever reason your follow up options are to either: not trade and probably take free damage, or put your self in more danger trying to place a Soldier next to your opponent. Even if you do hit them with Q, unlike a burst caster where you are only in danger for the duration of the burst, Azir has to stay in danger if he wants do damage. Otherwise, they just walk away from the soldier without being attacked. Orianna and Zyra are good examples of not being in danger for the duration of the burst.
Mid game skirmishes are what I love about Azir. Right when you get 40% CDR with blue, and Q and W are maxed, you get to move around the fight and kite and make interesting decisions. It's super fun.
His late game team fighting, on the other hand, is a little bland. You just put up your wall, and kind of stand there and auto attack the front line because you cant really get to the back line safely.
One last thing about Azir: its kind of hard to secure kills due to the nature of his damage not being burst, and not always being able to follow the fleeing opponent even though, by the end of the game, Azir normally ends up with the most damage by quite a lot.