Actually, that would just add to the nightmare fuel that is Minecraft:
You're (almost) alone in this world, the survivors are stupid and cannot talk, monsters roam the land, dungeons create hordes, there are ABANDONED FREAKING MINES with POISONOUS SPIDERS inside the world, with floods and areas that are blocked, there is a version of hell that has something called a "fortress" - with even more monsters inside it, there is an alien dimension commanded by a dragon whose only entrance are in 3 strongholds that have prision cells and a library.
Ars Magica's diaries are also preety scary: there were people before you in this land. What happened to them?
Anything that contributes to creating the feel that the apocalypse has happened and humanity has been wiped out from the face of earth/developed itself to the stage of testificates is kinda scary.