Fast Travel changes -
Morrowind style fast-travel with some added tricks. No more instant teleportation to various parts of the map.
Boats docked outside cities (Doubt there will be many cities near the shore in skyrim).
Horse Drawn carts that will be stationed outside the city gates. These carts will constantly be on the move, sometimes you will have to wait a few minutes for one to arrive. While out exploring the wild sometimes you will run into a Horse Drawn cart on its way back to a city you can pay to get a lift. You can even chose to watch the ride in "real time".
Time scale slowed down.
To maybe 10 minutes = 1 hour in game. You can "wait" or "sleep" as usual.
Basic survival needs
The need to eat sleep and drink each day to stay alive. Water being the most important thing. I always thought it should be similar to world of warcrafts hunter pet mechanic. For those that don't know it would be like this. Eating a huge meal and being 100% nourised would make you do 150% damage (Well nourished). As long as you stay well nourished you will stay at 150% damage. Eating normally would make you do 100% damage(Content), eating just enough to survive would be 75% damage(Hungry).
You can survive for a long time without food as long as you are drinking water. After 3 days of no food your damage will go down to 50%(Starved) and will go down 10% each day after that until death (0%).
Sleep would use the same mechanic but instead of Damage it would use fatigue. Sleeping 7 hours a night can give you 150%(well rested) fatigue, letting you run, swim, jump for longer.
Sleeping 3-5 hours each night would give you 100% fatigue (content) and sleeping ony 1-2 hours a night would give you 75% fatigue (tired).
After 3-4 days without sleep your fatigue will go down to 50% (fatigued) and will go down 10% each day until death (0%).
Leaving cities should be a big ordeal.
Leaving the confines of a big city should need preparation. You won't have constant food, beds and warmth. You will need to make sure you have enough food and water for the trip, your bedroll and whatever else is needed. Leaving a city to spend a few days in the wild should be dangerous. The player should be wary of disease, injury (from getting attacked) and starvation.
Weather to effect player.
Sleeping in a snowy region out in the open may give you diseases such as frostbite (-20% fatigue). The player can perhaps cast spells (Frost resistance?) to shield from the cold or wear a fur coat under his armor. Perhaps the player will need to find an Inn or a cave to sleep in to shield him from the cold.
All of these things can easily kept in order but if you let it get out of hand you will find yourself in a tuff spot. Imagine being in the middle of nowhere an Inn miles away and you have 25% fatigue (No sleep and frostbite), 50% Strength (Starvation), you can only run for a few seconds before you have to walk again and if attacked you don't do much damage. Not an ideal situation.
Maps
Maps in "hardcoe mode" will not be explored. Major cities and the roads connecting them will be shown on the map, everywhere else will be grayed out. Places you explore will no longer be faded out. You may find maps on your travels (in caves, on dead bandits etc). After finding these maps you can click "compare" and anything new will be added to your map (locations such as caves, hideouts etc). You can buy maps from traders, inns etc or you can even ask random people "places of interest" and perhaps you will add something new.
I think I have left out a few things but I'm in need of some food myself (75% fatigue at the moment) so perhaps I'll update later. What do you guys think?