Just realized Azir has not being seeing any competitive games this year

A couple reasons:

Azir has terrible synergy with every good AP item nowadays. He wants to build Nashor's Tooth, which honestly isn't the best item currently, as well as a very expensive one compared to most other rush items.

Azir was very popular in S5 because most assassins were very out of the meta. Now that Zed, Leblanc, Ahri, Lissandra (she's a pseudo-assassin), and even Rengar have been seen a bit recently, his counters are far more popular and easier to pick against him.

He's been nerfed repeatedly.

Other champions can bring what he brings, especially Corki.

Easyhoon destroyed with him yesterday...

(http://www.lolesports.com/en_GB/vods/lpl-china/lpl_2016_spring Vici vs HYG "Day" 3 Game 2)

What the hell happen to him?

Not that much, he's still seeing a lot of play in Korea.

Yes ,True.This guy has only 5 Azir games,only 5.You don't mention about Azir.Only comic.

Azir is fine the way he is. Leave him be please.

Riot destroyed him.Nerf,no mana buffs(for patch 5.22),also Riot buffed other champions,ad items.He needs buffs.

I will tell you the story of SHURIMA

Azir stormed onto the Rift with both haste and confidence. Azir was strong, and he knew this. Azir was powerful in laning phase, Azir was powerful in teamfights, Azir was powerful, but never unbalanced claimed Azir supporters, the Riot gods did nothing to tame him.

And then Azir scored a 1v5 pentakill in a LCS game. The Riot Gods were appalled at this blatant disrespect for fairness. They took Azir, removed one of his passives (he used to have two) and took away his knock up. This was just the beginning of the great emperor's downfall. Piece by peice they took damage away from Azir, until he was the Trollpick that he is now (cue music: Coldplay - Viva la Vida)

But serioulsy, he used to have a passive that gave his 1.25% attack speed for each 1% CDR he has, instead of nerfing the passive, they just removed it. His Q, the one where all of his solideirs dash to a new position, used to have a 30% damage reduction on each solider hitting an enemy after the first, and another 30% on any solider hitting the enemy after the second. They changed this so that now only one soldier can do damage. He E, the one where he dashes to a soldier, used to knock up the first enemy champ it hit, and give Azir a shield based on his percent bonus health, they removed the knock up and since the shield scaled off of BONUS HEALTH it was just a crappy shield and they left it alone. There are still glitches where his ult will go the wrong direction, won't knock people back, using a Q will cause soldiers to dash in weird ways if you have 3 of them up.

Before when Azir had his passive, building a Nashor's Tooth was obvious, since you would get so much attack speed from it, but now you have to question if you want Nashor's Tooth for AS or get a Morellelonomicon for the mana regen and Grevious Wounds. The only Health item that would be good is a Rod of the Ages, which is really pricey and takes a while to get stacks. Even at max stacks, the shield that results from his E is so minor that without the knockup he is at great risk of getting melted as soon as he tries to dive the team for a good ult.

Azir used to use several soldiers in the lane to both farm and zone/poke the enemy laner. This was a lot of fun, because it was difficult to keep track of all your soldiers, use them properly, and remember that any Q would displace them and you'd be stuck farming with autos, but it also made you feel powerful, like you were commanding an army as an emperor. Now having more then one soldier up at a time is more often a waste of mana.

People are playing a lot of ADCs in mid at the moment, that might have something to do with it.