Villagers are a great feature of Minecraft. We can trade with them or even steal from them. But I feel as if the villagers are sometimes a bit dull. I think a great way to liven them up would be to add some more interaction with them. For instance, you could give a blacksmith food, and he would smelt a certain amount of blocks for you, depending on how much food you gave him. Or perhaps you want some extra meat. You could pay a butcher emeralds or iron or something else and he could kill a certain amount of animals for you. To prevent exploit, there would only be a certain amount of items you could give to him. This sounds like trading, but this way you could go mining while the blacksmith is smelting the iron for you. Please offer any ways to improve this idea in the replies. Thanks.
The existing trading interface already emulates what you have suggested. Give a butcher an emerald and he gives you cooked meat. You need to pretend that he had done all the killing and cooking already.
If you mean the villager should actually go out and do those things (killing cows, interacting with furnace, etc.) it's completely unnecessary. Besides, like BP said, why pay a villager when you can do that stuff for free?!