First off people say Zed takes no skill due to his complete lack of risk when going all-in. He has a ridiculous amount of damage output and can instantly just jump out of a fight if he needs too, not too mention he's quite difficult to gank without coordination with your own mid laner. He isn't an "easy mode champ" at all, anyone not stupid as fuck knows this, but his mechanic skill requirements are kind of offset by his ridiculous kit, so people claim he's easy to play.
Secondly, I've never heard ANYONE say Azir was easy to play, I've heard people complaining about his damage output, but never about him being easy in the slightest. Whoever said that to you is simply stupid and you should have just muted him instantly cause he's obviously a liability more then anything anyway.
Third, Ekko isn't even out yet, only on the PBEs, so we have no way at all of knowing if he'll be Azir-difficult or Diana-easy until he's live and available for everyone to play. He could for all we know be as brain dead easy as Diana, his kit is similar afterall, or he could be more difficult. No way of saying for certain, so don't even bother arguing about it with anyone, just a waste of time right now.
Finally, every ADC is easy to play, anyone claiming they're difficult is obviously just an ADC main who doesn't want to admit he plays easy champs.