Blizzard has created what I like to call of 'virtual' content.

Literally everything you do in legion has only a chance of giving you a reward, you have no guarantee that your efforts are going to be rewarded, you can spend 200+ hours grinding for an item and someone else got the exact same item after spending 10 or 15 hours.

Just imagine if Susanoo had only a 5% chance to drop a weapon and had no token, people would be running parties for Susanoo for months after the launch of the expansion and still not everyone would have their weapon. And that's not all! There is also a chance that your weapon will have a 5 ilvl upgrade or a even smaller chance that it will have a 10 ilvl upgrade, and there is also the chance that it will have extra sockets for you to put materias on, or some random stat that buffs your movement speed or survival. Do you call that actual content? That's basically what Blizzard has done.

Now, I will agree that SE could add something here and there to increase the content longevity.