please stop misusing the word casual. the amount of time one plays has no correlation to how skilled one is. the more proper word would be unskilled. besides all content that the average ex wow player can't complete in a few tries gets nerfed now.
I don't think I ever defined, or would define the word "casual" based on how much time one plays.
To me it means "Desirous of nerfs on content which can/has been beaten by others", or "wants loot handed to them without any real effort put forth". Or perhaps "one who plays games not for the sake of a challenge/mental stimulation, but moreso for social purposes".