It could be interesting for some players.
However, I think your idea straddles the line between hardcoe (as in the New Vegas hardcoe mode, more immersive, survival/roleplaying) and hardcoe (as in FPS or Diablo 2 hardcoe mode, difficult for the sake of being challenging) which are quite different.
If the devs decide to implement some sort of saving restrictions, perhaps they will incorporate that into the difficulty slider (highest difficulty setting) rather than hardcoe mode (if there is a hardcoe/survival mode).
Some of the New Vegas players who wanted the most difficult combat experience possible found the survival (eating/drinking/sleeping) aspect of hardcoe mode frustrating. Some others who enjoyed the survival aspect chose to set their difficulty slider to Easy because they found the combat too difficult. Personally I went with hardcoe + Very Hard, but I probably would want the freedom to save anywhere, especially since I will not be using any fast travel, just walking everywhere (or riding a mammoth
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