Although I don't have a LOT to offer in this thread, let me say this one thing. Although it is true that Zygrade having the potential to beat Azumarill shows a bit of viability, let me point out something
Azumarill isn't exactly a very difficult pokemon to counter, so I don't see why the Azumarill argument is so important in the first place, its much more important to see what else it can counter and/or what sets/etc are viable on this Pokemon. I just feel like the topic has been directed the wrong way. I see why, if a Dragon type is able to take out one of the biggest fairy type, then it has some worth. But there still a chance that Azumarill might be able to take out this thing if not used right, and considering my gripe with Zygarde is that it is a bit obscure and difficult to use, its a little unattractive to me. Its one of those pokemon that is fantastic if the pokemon is used right. And I'm not exactly sure if Zygarde is worth the strategy that needs to be used. Although Zygarde is a viable pokemon, I'm not sure if its good enough to compete in the OU tier.
If I insulted some of you, sorry, and if some of my opinions are false, then I'm sorry for that too. I'm not exactly the most "competitive" player, but I do have some sort of say in this argument as I do have some experience in the metagame.