I used to play WoW before...
When pandaria come out Blizzard introduce boost system... I'm completely mad about it.
They introduce boost to help new player to catch up veterans but the drawback is many boost player at raids who doesn't know anything.

In leveling progression there is story and lore in it, they taught us about the class and learning curve in it for the basic group mechanic just like guildhest.

Later on most of the veterans will no longer go there, so if we have npc that would be nice.