Here is what I suggest:
The same as NV (you need sleep, food and water)
ALSO that before you start the game you have the option to choose hardcoe mode like we had in Diablo 2. For people that haven't played Diablo or doesn't remember, it forces you to to exit game every time you save, and when you die you would be dead infinity. I know some of you think that is TOO hardcoe, but it adds realism and when you think of Fallout NV, it was a bit too easy to make money in the casino plus the speechcraft options because you could just save right before the decision and then reload if something goes wrong! This will definitely solve this problem.
I know that it may be hard to survive in Skyrim, but then sometimes you have to flee, something that I never used in earlier Bethesda games. Also it would be cool if you in some way could 'buy' an item or a buff (maybe send from the gods) that revives you only one time if you of some reason dies.
It would be cool if you guys would give some (constructive) critisism and say what you think!