In Fallout: New Vegas, Obsidian added some new features to the game’s Hardcore mode. These included making sure you sustain yourself using food and water, as well as needing to get enough sleep. You also had to use special items to restore limbs, and companions could be killed in combat. Fallout 4’s Survival mode, on the other hand, is a bit misleading in its name, as it primarily makes the player take a lot more damage and give out less (it really should be called ‘hardcore mode’, and New Vegas’ most difficult setting should be named 'Survival mode').
Skyrim’s ‘Realistic Needs and Diseases’ essentially brought New Vegas’ Hardcore mode to the game; making eating, drinking and sleeping a necessity and causing serious debuffs if players ignored those basic needs for too long. There’s no doubt that a similar mod will eventually arrive for Fallout 4, and on top of requiring players to eat, drink and sleep, it’ll probably make radiation a lot harder to remove as well.
You can download Realistic Needs and Diseases here.