Raids are the least popular endgame not only because the difficulty is hard.It requires perfect harmony in skill and forming same schedule/skill competent groups for long play sessions on a regular basis.
The point here is watching the metrics. If 4-15% of the playerbase is getting new story completing raids and the rest aren't. Something is amiss. In a sub based game, isn't the point of a dev to try and get the most players possible having a reason to log in? If it's not, then the game should go full on hardcore and then they would have a couple of hundred thousand that never quit, but everyone else not in that category would fly the coop.
Normal should be pretty difficult, but not Savage difficult, more lenient towards pugs and mistakes. Savage should have the BiS and require statics, guild type content but just marginally better or you get a cry for content from both sides. The super elite saying the rest of the game is too easy and the other side who says the game is too hard.