Azir is a fucking monster. He's not ez-mode faceroll, but if you crush out some games, and actually figure out how to play him, he's one of the strongest casters in the game, and can be built tanky AP bruiser top.
Just don't play him against strong assassins with spammable gap-closers or high mobility. (Read: Zed, Yasuo (MID), Jarvan, Xin, Kass (TOP)). Playing safely vs these champs he can still survive with his insanely long range.
Been spamming him on my smurf for free elo. Play him until he reaches permaban status (I've already seen him starting to get banned).
Ideal runepage:
Hybrid pen (or magic pen) reds
1 (or 2) armour yellows - to prevent being base armour if they click your champ info
8 (or 7) scaling health yellows - his shield scales insanely well with health
cooldown blues
Flat AP quints, but anything can pretty much work for quints
If you have a rough matchup, run very defensive runes, and survive until his absurd scaling takes over and you start crushing. (Ie. Hybrid pen reds, flat armour EVERYTHING else).
Top: TP+Flash
Mid: Ignite+Flash
Top: RoA -> Liandries -> Lucidity Boots -> Rylais -> Randuins -> Banshees
After Rylais/Randuins, your shifting sands (when you knock someone up) shields for about 550. This means you can W->Q->E to engage on someone, then ult to split the fight in half.
Mid: RoA -> Deathcap -> Lucidity Boots -> Rylais -> Nashors Tooth -> Void Staff. If they aren't building much MR or you feel you are still doing INSANE damage even without Void, you can go Liandries which makes his Shifting Sands much stronger in dire situations.
I bought him and spammed like 10 games with him, and came to the conclusion he's absolutely fucking garbage. Then I realized I'm garbage and he is a rapefield, you just have to know how to play and build him.