A. Ok the purpose of my mine idea is to add some meaning to minecraft from a midpoint throughout the game. So far you are free to roam and survive and create but besides finding dungeons and villages there isn't quite enough yet to satisfy a hardcore player, especially in single player.
My idea is add a plot to the game as in a random side story. By using mechanics already in minecraft I think Mojang can greatly increase interest in the survival mode of minecraft. Notch/Jens were on the right idea about adding random buildings into the game but what is there now isn't quite enough.

B.
Events briefly described:
- All events use villagers talking
- Each event depends on the biome the village is located in

1. [Plains: cobble and wood houses] A dark dressed villager is born after triggered events which villagers talk about being bad. After another trigger the villager dissapears and a castle (above ground) can be spawned in a new chunk. Castle contains a unique mob (villager guards), maybe a droppable book enchant (better emerald trading), and the bad guy boss (the bad villager).
The castle will include a potion room and maybe a witch there, randomized hallways with guards and items frames on the walls, and the main throne room with the boss. This will use the same coding as a fortress. Coding villagers to talk somehow, they can tell a story of this villager going out on his own or something.

2. [Desert: Sandstone houses] The sand temples that spawn in some villages could be expanded a small bit to make the descent into the treasure room a bit more interesting. This event will include one villager being born after certain triggers that will talk about the nearby temple (even if there is none) and how he/she found a special item to unlock the treasure room. The treasure room will need to be either surrounded in something like bedrock or will have a portal to go to it, just something to prevent the player from going to it. Well basically the villager will be buying a rare item like something additional dropped from the dragon boss or wither boss. Once you trade him that new item he will give you a key that unlocks the treasure room. Also a new bigger looking treasure room wouldn't hurt, Jens.

C. I am certain this idea will lead minecraft in the right direction, even if my specific story ideas above aren't considered I still think there should be some expansion on the existing code to improve villagers and create interactive plots. I tried not to lean toward a lot of new coding, but what I did mention would be totally worth the effort.