Time investment is not even in the general area of casual or even midcore players. Reasonably playing, its content for at least 3 hours daily of high end content most casual players are not interested/able or have the time to do.

In fact, casual players are for the most part, still doing 2.X relics, so in all honestly, 3.X relics are defenitly not for them.
Some people define casual by time investment, others by "do they raid or not" and others again by whatever other criteria you could have. Decide already. But don't equate them all "it takes a while, therefore the only one who have time are raiders anyway", cause that's crap reasoning.