I would love a good hardcoe mode, but Bethesda's attitude of do-whatever-you-please really is priceless in TES.
If they want to keep that attitude, wouldn't adding in hardcoe mode contribute to it? After all, doing whatever you please should entail playing the game the way you want too, and adding the option to use hardcoe mode (And if you have to call it a "mode", that would already suggest it's optional, if it was forced on players, it would be a "hardcoe system" or something.)
But I've actually been thinking that if Bethesda wants to appeal to the players that are obssessed with realism, following Obsidian's example with hardcoe mode in New Vegas would be the ideal way to do it. I'm not sure if the implementation in the game itself is necessarily ideal since I have not experienced it, and in any case, even if one wouldn't want to change hardcoe mode at all in New Vegas, the nature of the Elder Scrolls might demand a somewhat different design, after all, while eating, drinking and sleeping could be expected, in the Elder Scrolls, arrows already have weight so unless that changes in future games, you can't very well make ammo weight a feature of hardcoe mode. And no Elder Scrolls game so far has had a crippling mechanic. I guess potions could be given healing over time, although a least in Morrowind, potions made by the player already tend to heal over time anyway, maybe also a limiting the player to one potion with each effect at a time, or making potions take time to drink or something. Also, diseases could be made into a more serious threat, maybe their effects should be stronger, or they can get worse over time or even kill you if you don't cure them soon enough, maybe you also wouldn't be able to swim when wearing heavy armor. Also, if we assume that fatigue works like in Oblivion, in other words, it doesn't go down while running, it probably should in hardcoe mode.
Also, I'd change the name to "realism mode" or "survival mode" or something, since a word like "hardcoe" sounds kind of out of place in a psuedo-Medieval fantasy setting.
Dead-is-dead maybe a separate checkbox too.
If you really want to play the game that way, it doesn't need to be a checkbox, you can just exit the game if you die, delete all saves of your current character, and start a new one.