i was thinkin , maybe there could be like global quests like seeking the holy grial, really hard to get, and it gives you some kind of distinction of the rest of the players, and since there has to be more, there could be other relics like pieces of the cross, etc... and then after someone gets it he has to be challenged by other players for the relic, and so older players don't have advantage, there could be a whole guild fighting only him, according to the level difference
its pretty raw idea, hope pple like it and make it better
btw xaoc mentioned smt about epic quests or smt, but as idk i wanna post it anyways