I understand that Villagers should be protected by the player, but the way it is as of now isn't that fun. If this is to be a thing, the following needs to happen:
1. Each village starts with at least 1 iron golem as aid for both the villagers and the player.
2. Zombie sieges (or other similar events to be implemented in the future) should be the only events in which villagers should die without player aid, and the whole event of a zombie siege should be better communicated to the player.
This may be what Minecraft is to you, but it isn't the same game to everybody. Many people play it in many different ways. That's part of why it has been so successful. Also, I don't see how this is any more "thinking financially" than trading with Villagers yourself- this is merely an extent to that mechanic to player-player interactions and a purpose/use for the Nitwit.
I really like this idea. It's creative, smart and makes me also wonder why Mojang didn't add this. However, I notice a few issues, the first being "Provide sufficient protection for Villagers." [/b]To me, I think Mojang hasn't added this because of the fact that protecting villagers should be your job. It creates a fun challenge and is something I think taking out would almost make villages to easy. I know, it's a weird idea, but I still think it's a good one.
Also, hiring nitwits is a problem for me. Adding a store in which you own to me would add a complication to the game that is unneeded. Minecraft isn't about buying and selling and thinking financially- it's about trying to survive in a world without things like that.