Encourage low level/all level play by bringing up low level awards to match high level, unlock all zones and content to all levelds (yes even incarnate), and create new gameplay which favours low levels. Who will that hurt? The egos of people who "earned" the entirely pretend and make-believe powers, maybe. But that was trained behaviour of sunk cost fallacy to maintain subscriptions for money. Time to get over it and just let everyone play anything. Some people will get bored and leave sooner rather than later but those are also the people who say the game is already too easy with nothing to do.