hardcoe mode with the following, and this is gonna turn into a long one:
1) Options for the hardcoe elements you want to have active. Some claim FONV hardcoe to be "tedious" (I don't), so why not let people choose just how tedious they want it? It also makes sense in a traditional role playing system in that the players can discuss with a GM what elements should be focused on. Role Master have rest, eat and drink, but you could come to an agreement where these matters less. Often there are even rules described how such "simplification processes" are to be approached.
2) Split the bars into three parts (this is part of "basic needs"). Currently they are split into two - remaining and reduction.
|||||||||||||||Magicka Damage|||||||||||||||||Magicka Remaining|||||||||||||Magicka Used||||||||||||||||||||||||||Health Damage|||||||||||||||||Health Remaining|||||||||||||Health Used||||||||||||||||||||||||||Stamina Damage|||||||||||||||||Stamina Remaining|||||||||||||Stamina Used|||||||||||The Magicka Damage will increase each time a spell is used, lowering the maximum potential magicka you can regain through regular regeneration and potions. To regain full potential, you have to sleep (not wait). Is there are to be a secondary possibility, I'm not sure what this should be, but not potions.
The Health Damage will increase each time you take a "critical hit", lowering the maximum potential health you can regain through regular regeneration and potions. To regain full potential, you have to sleep or visit a temple (a shrine in nature won't do).
The Stamina Damage will pretty much increase all the time as long as you stay awake, further sped up by not eating. This can be halved by eating quality prepared meals (not raw materials). On exhaustion you simply collapse, but I don't think Daggerfall's "die from it" is really needed.
Basic Needs:
Sleep - Restores pretty much everything, how long depends on quality of bed (where it is - dungeons, and weather should matter if outside). Any diseases you might have should also force damages, which other than being realistic also serves as a visual indication that something is wrong. Currently everytime I get a disease, I find out about it from someone telling me. It's silly. In real life, if I'm sick - trust me - I know.
Food - Increases health and stamina over time. It also give a prolonged effect on regeneration time for normal regen of these two bars. Combined with sleep, it restores them fully except for disease effects that affect them.
Water - Same as in FONV, simple drink animation from water sources. They are so frequent we don't need additional carrying beverages, maybe except the possibility to fill up empty wine bottles. If you don't drink, the damage stamina bar will rise more quickly over time.
Hypothermia - Affects animation speeds directly. You will walk and run slower, swing your sword slower, prepare your spells slower, and significantly reduce the sweet spot of locks (try doing fine mechanics while freezing). It comes from operating in cold areas without sufficient insulation (clothes), where multipliers for the speed of gathering hypothermia points comes from being in freezing water and wind chill factor. Some races may have builtin resistances for these, like Khajitt fur protecting against wind, and Argonian not feeling water effect, while Nords already have buildin resistance to it.
Degradation:
Weapons and armor should again degrade, but not like in Oblivion. Instead let the quality level degrade. Something similar could be invented for enchantments. Also, it's very important that we can choose to let the armorer, mage, or alchemist perform these things for us, for a significant fee of course. Basically we're paying for NOT skilling up, which some of us are actually willing to do in order to stay down in levels, yet have access to the equipment. Opponents should get varying levels of equipment qualities as well. Speed of degradation depends on what material hits what material, using the smithing tree as a guide. Use an iron dagger against elven armor, and it will degrade fairly quickly.
A weapon should also have a "health bar" so that we can monitor progress without having to open the inventory. A "weapon health bar" could also be split into three, where the leftmost "weapon damage" part reflects pure corrosion that happens over time. Only daedric artifacts should be totally free from corrosion, and you can't "repair" this. Perhaps bandits and other low lifers tend to get fairly corroded weapons, which also affects price? Maybe "corrode equipment" should be brought back, with the penalty this time around that it can't be fixed and will decrease the value of your loot? Corrosion happen while swimming in salty waters (extreme corrosion), in fresh waters (heavy corrosion), drawn weapon in rain (moderate corrosion), and drawn weapon in misty dungeons (light corrosion).
Followers:
Options for "followers can die" (from enemy engagements) and "followers have limited ammo". Maybe double their health if their die option is set.
Armor values revised:
Somehow fur shoes are higher rated than fur boots (iirc). And the various fur armors have the same armor rating, even if one of them covers pretty much nothing at all

Here is where I go "but this makes no sense".
Grinding that makes sense:
The concept of grinding iron daggers to smithing master makes no sense at all. Force us to craft in a matter that makes sense, like crafting higher level items in the list, in order to gain anything from it. Those that doesn't want to perk up can still buy the skill, and have nothing to complain about imho.
Adjustable points when leveling up:
Let us be able to lower the amount of points we get from leveling up. Even on master I tend to grow too powerful far too quickly, and it doesn't make sense having to put points into magic as a fighter just to make the game more interesting. Maybe leveling should be a paid service? It worked back in Bards Tale times, and the money you spent determined how much points you got? Money is hardly a problem in this game anyway, even if it didn't have to be super expensive - it leaves the player in control of his own gaming rather than having to nerf everything he does.
Weights:
Arrows should have weight. Different pelts should have different weights in order to create leather of different weights. Doesn't make sense to me that tanning a certain pelt actually increases my total weight.
Market:
Simulation of "market saturation" that lasts a week or so. Sell the same stuff over and over, and the price goes down and the skill xp gained goes down as well. Finish up the business ledger mechanic that is suggested throughout the game as well.
Well, I have tons and tons of more ideas, but I'm gonna close it before thread reaches that dreaded post limit again...