WoW is certainly a MMORPG, you don't need a "living, persistent world" to be a "true" one.The primary issue you describe can be explained as this. WoW is NOT a true MMORPG.
Not a living, persistent world. Cataclysm update aside... WoW's world does not change. Instead WoW is an online themepark game with a new set of rides every 2 years. Legion is the newest set of rides and none of the older rides, the "world", will reflect it because old rides generally sit and collect dust. Again, this is how WoW is not a living world. The static nature of the WoW formula where you might never again have a relevant storyline in Azeroth, Outland, Northrend, Cataclysm zones, Pandaria, Draenor, or Broken Isles GREATLY harms the narrative and nostalgia that would accompany natural storytelling.
With a static world we lose the "feel" of the world. We lose a compelling sense of place and belonging to WoW itself. For example, Suramar is a great place. You will never see it again. Let the implications of that sink in. WoW is great for what it is (online themepark) but that design has serious limitations.