I love the idea, but I hope for it to be a map specific thing, or an option in the menu so those who only wish to roleplay don't need to worry about hunger/thirst/health.
The simulation thing would be more of a plugin that you can turn on or off. Of course, turning it off while in the middle of getting hurt or something to gain an advantage would be simply poor behavior and would be a good way to lose respect
Kinda like people who god mode in roleplay