A hardcoe mode in Skyrim would be a good way to reward players who want to avoid using the fast travel from the map to make the game feel more immersive. As with hardcoe mode in New Vegas, I'm sure needing to eat and sleep on a regular basis would be a requirement. Maybe the game could impose unique requirements depending on the character you choose. As an example, Argonians might need to spend a certain amount of time in water each day. And while unlocking an achievement for beating the game on hardcoe mode would be the expected reward, it would be fun if it opened up an interesting and unique set of armor, weapons, player house, something concrete in the game.