casual players should be getting close to all legendaries for their mainspec by now if they didn't swap specs and raid a little here and there.
not having all your legendaries for all your specs is still normal even for hardcore players.
the system sucked really bad early in legion but now when you can get a legendary every 2-3 weeks if you put in some effort i think it's fine. Still they should have added a way to target a legendary earlier and better.