Well, let them remake the world, but have the gems show them the consequences of their choices beforehand, from their perspective. If they choose All Life/No Death, they see hordes of crippled elders, unable to pass away because there is no death. if they choose all Peace/No War, they see a world where no one stands up for anything, where no one braves the odds to make life better (because there is no ambition to improve, which can lead to war, but in a smaller scale is needed).
After the world is re-made, the gems teleport to the end of this new world, waiting the day where they will re-make the world again.