I would like to see a farming system:
You would be able to plant crops, farm animals, farm fish.
Planting would have to ability to place and object and have a variable number of states of growth and ability to set the time for that growth.
When reaping, the farmer would be able to get seeds as well as crops.
Animals would be able to bread and provide meat, wool, hide, etc.
There would be a method to be able to add to the functionallity with my own models.