Add more puzzles (love those). Allow the villagers to expand their horizons and explore the rest of the island (that little patch of earth can't be all there is). Maybe go through the cave and come out the other side. Allow more hut building after the expansion so the population can get bigger. Have one Master Whatever be a teacher so you don't have to go through the hassle of "traning" a young villager how to do whatever it is they are going to do...including being a parent.