I suggest, on the side, quietly have the developers make a new world. It would be a world that entails levels 1-20 and can be upgraded along with level limit increases, etc. The catch, though, would be that only true reincarnated people can enter. Thus, when someone reaches level 20, they could opt to reincarnate and be born in this world. There could perhaps be a gateway between the two worlds, but the new one would be strictly for those who have maxed out and are starting over. The world could cost some modest amount of Turbine Points or be available to VIP's. Thus, people can level up to 20, run epics until they've had enough of that, then reincarnate on an entirely new planet with new places to explore and new dungeons to conquer.