Why are we nerfing Azir but buffing Darius?

Azir is in no need of nerfs, he is a skillful champ that requires talent to play well. But Darius who is seriously broken right now is getting a buff. There was a front page post early with a darius getting almost 2000 hitpoints back from one Q.

EDIT: Here is the thread with the Darius video. http://boards.na.leagueoflegends.com/en/c/gameplay-balance/Fx4ZBvXH-why-is-darius-not-disabled