I have played quite a lot of Azir (about 60 games) before and after the nerfs hit. He was definitely too strong before the nerfs, especially the ultimate duration. 2 seconds now may be short, but for pros, it's still enough time. I'm far from having mastered Azir but he is very weak to ganks early on. Cheese lvl2 gank works amazing on him, since E will not be leveled up until 4.
However, doing W-Q costs mana, and if he tries to poke you too much, he will end up oom and will have to choose between farming/harassing.
I also played a fair share of games against him. Obviously a range mage is very good. Standing besides minions will help: If he pokes you down with Q, he can't clear waves after. Also a lot of Azir don't master the Q range so always keep the distance with AZIR and not the SOLDIERS.
Once he got some levels and AS, don't try to trade too long, clear up waves and wait for teamfights. Most Azir including me at this stage will push the waves ASAP, so you won't lose CS if you are a bit patient.
On the PBE I think there is a nerf to his soldiers damage. It will actually be lower at early levels and scale up to his regular damage late.
This is a fair nerf IMO and I'm ok with it.