There are obviously 2 different ways to build Azir:
AP based (Deathcap, voidstaff, zhonyas) which is more early game based or Attack Speed/CDR based (Stinger, morello's)
I personally prefer the dps build, and i'm curious as to weather attack speed runes (quints+marks) would be better than AP. Not having ap runes would make him sucky early, but he is anyway so you should avoid fights at the early levels anyway..
Any thoughts?
Ternt1 votesWhen I play, I usually go with Ludens, Deathcap, Zhonya's, Nashors, (situational item), and Magic Pen Boots. Runes I usually go with scaling cooldown glyphs, armor yellows, attack speed marks, AP quints.
EDIT: He doesn't suck early, he has insane poke damage. You out farm and harrass your laner no matter how much AP you have. I wouldn't look to team fight until level 4 at least, but 6 would be preferred. Purely based off of his E and R at those levels. I level his abilities W -> Q -> Q -> E -> Q -> R. Since Q is his biggest form of poke damage outside of auto attacking.
Seventh Lion1 votesThere are obviously 2 different ways to build Azir:
AP based (Deathcap, voidstaff, zhonyas) which is more early game based or Attack Speed/CDR based (Stinger, morello's)
I personally prefer the dps build, and i'm curious as to weather attack speed runes (quints+marks) would be better than AP. Not having ap runes would make him sucky early, but he is anyway so you should avoid fights at the early levels anyway..
Any thoughts?
Well if you gave up those runes, you'd get roughly 11% attack speed. Which isn't that great.. for the AP you're losing early game. Cause you want to be able to secure a few kills early game our Azir can be completely useless.
Ahurath1 votesAzir got a prety bad early game so therefore you should have runes to help you get through the part where he is weak.
The Bard Dog1 votesi run 15% flat cdr. magic pen, and scaling health per level as azir.
then i build 
get a pretty substantial power spike once you finish void/liandrys
UberAffe1 votesI go straight attack speed runes against immoble champions (41% attack speed from runes) because I know I will have time to make use of the attack speed(which does technically outdamage straight ap if you can get off attacks) it also makes last hitting easier. But most mids are mobile so I go ap and mpen because I will likely only get an auto q auto.
qjVlKPSw5f1 votesAll really good feedback thanks guys. I Often build morellos into stinger and get the 40% cdr, so opt not to take cdr runes or masteries, interested to see how ludens echo is on him.. as i feel it is an item that people are building on the wrong champs (anyone that uses AP), whereas it clearly benefits some over others, such as xerath.
JQKAndrei1 voteswhy would you get AS runes when CDR runes give you x2 AS?
Maybe only if you want to buy the 40%CDR from items and get more AS lategame but I believe midlane runes are more for early game than lategame.
Totalwanabe1 votesbecause there's a 40% cdr cap with you get half nashor and other half from your mana reg item. while trying to get ats 2.5 cap is pretty impossible for azir unless you want 0 ap azir
qjVlKPSw5f1 votesIt's very common for people to use CDR runes on him.. but those tend to be the people that aren't using morello's, however I highly prefer having it. And i've yet to see attack speed runes on any builds i've looked up so hey, #breakthemeta.
Totalwanabe1 votesthe ats from the cdr cap and nashor tooth is all you really need rest is better suited in ap or survival. for rune you don't need any crd or ats so go for (ap/mpen or survival)
dEAdbUs1 votesAzir doesnt need AS runes or items. Only cdr. No more discussions. You may check any diamond or challenger runes and items.
Kazaashi1 votesNashor's is pretty bad on Azir, in my opinion. He needs a ton of AP to make each soldiers attack count for as much as possible, not more AS to make them attack faster. I find people usually move out of the soldiers range pretty fast, so they usually only get 1 or 2 attacks in before the enemy is out of range.
CDR is the way to go, but don't think of 40% CDR as Azir's power spike. It's more of a requirement because it allows you reposition your soldiers the faster and for them to put out a ton of dmg. I normally go Morello's first and then the CDR boots. 3rd item is either Zhonya's or Liandries or Deathcap. 4th item is usually Rylias. Most of my Azir games don't make it past that point.
N0TY0U1 votesYou have 2 option for runes on azir: 1- Flat cdr Quints, Glyphs, Marks and seals. With masteries you get 25% cooldown reduction at lvl 1 and only need boots of lucidity to reach 40% cdr. You then can build high damage items like such as Deathcap, Luden's Echos and Archangel staff. 2- Scaling cdr Quints and Glyphs along side Flat cdr Marks and Seals. You then have 12% cooldown reduction at lvl 1 and 40% at lvl 18. That way you don't need to buy those stupid boots and can build one more damage items.
With support Azir you should pick option 1 since you have the Intelligence Mastery and 10% cdr on your support item, you also shouldn't buy boots. Otherwise some of your cdr would be wasted.