Here's a list I want to see, but first a little background of my bias towards this kind of playstyle.

I'm a big fan of DayZ, Diablo 3 hardcoe and other rogue like games.

I played skyrim alot with hardcoe survival mods, such as losing gear upon death, food, sleep, cold indicators. If I mess up, like didn't bring enough food or was wrongly clothed , I died. And it was great. Death in bethesda games have usually little consequence as you can just savescum a lot. Having real consequence of losing all the stuff you are carrying gives the idea of having stashes around a better meaning, since you got to have backup gear in case you lose the good stuff.

Here's what I want in the updated Survival Difficulty.

Shortened time to death for players and NPC:

First, increase time do death. Both for players and NPCs. You doing less damage and the NPC having more health is not harder. It's a general misconception that an enemy is hard if he has a lot of health. I currently use a mod that increases damage done by 3x for all parts. And it works surprisngly well. It only takes a few moments of being out of position to die, same goes for the enemy. It shouldn't take 10 .50 cal sniper rounds in the head of a supermutant to get them to die, they are made of flesh and bullets go through that.

Bullet scarcity

I always end up with a massive amount of bullets and never run out. In survival you should be forced to switch weapons around as there shouldn't be enough ammo to just perma use a gun type constantly. This works well with shortened time to death as you will need less bullets to kill stuff.

Eat, Drink, Sleep

Real consequences for not eating, drinking or sleeping. Like being starving lowers your perception as health regeneration. Being thirsty limits endurance, tired limits charisma and luck. But being rested and well satiated gives bonuses.

More dangerous radiation

Even on the harder difficulties radiation is never a problem. Getting rads is just a minor inconvenience. I would love to see that if you are radiated for extended periods of time without curing yourself, it starts to take a permanent toll on your body that only expensive treatments can solve.

Money or resource sink

I would love to have some sort of sink I can pool my resources in to. I always end up having a ton of caps and being able to afford whatever. I have for example never ever had to buy bullets at all. With more bullet scarcity there would be a more incentive to buy bullets.

Items getting destroyed on killed enemies (durability and repair)

Totally disentigrating an enemy and then going to collect their pristine combat rifle makes little sense. Killing enemies in certain ways should effect how the gear is treated. If i blow someone up with a nuke, their armor probably won't even exist anymore. If you really want to steal someones gear, make sure you kill them in a away that makes sense so their armor / weapons don't get destroyed in the process. Being able to repair weapons and armor like we can with the power suit would be good too.

Durability and repair and jamming of weapons

I would love to see some sort of durability system. In skyrim I had a mod that made my weapons and armor degrade the more they got used and hit, if I didn't attend to them they'd get broken. I would love to see that here. Maybe not durability on rifles and such, but having to clean them after they get dirty or filled up with gunk from firing too many shots. Also having weapons jam and rendered unusable would be a good mechanic to encourage cleaning of weapons. It would also add an incentive to have more backup guns in case the one you had malfunctioned. A rifle won't break into pieces if you don't clean it, but armor might get shot to pieces if not repaired and mended after battle.

Losing gear upon death (different settings)

Death in Fallout 4 or Skyrim never really meant anything. You'd just load the last save and continue from there. No real consequence. I would love to see a system implemented (like mentioned before) When you die you lose all the gear you are carrying. And respawn at a settlement or in the vault you started. This is for the hardcoe and should have different settings.

1. All gear is lost upon death (except quest items, they stay on your body so you have to go back and get it)

2. All gear remains on your dead body, but you have to go back and get it, depending on where you die or what kills you, some or all gear gets stolen or looted. Take too long to get back there and all your stuff is gone. (Perhaps introduce a quest to get your gear back?)

3. All gear remains on your dead body until you collect it.

This would give the incentive to having stashes around different places and having supply lines between settlements if that is the route you go.

Penalties for fast travel

Fast travel should be an expense and not a luxury. In this hardcoe difficulty, eat, sleep and drink should factor, as well as fusion cores on power armor. If you fast travel across the map, then it should spend more power and eat, food, sleep than it would be if you went there manually by yourself.

Larger groups of feral ghouls

Zombies are awesome, ghouls are a joke, but not in greater numbers right?

Fixing the reload glitch.

Fast switching between weapons automatically reloads them. Huge gameplay breaker there if you use weapons that are strong but take a while to reload.

Visual low health indication.

I want to see an indication of when you have low health either visually (screen goes red and veiny) or have the character moan or make some painful noise to signal that they are hurt. Often I have been shot by weapons that don't really give any kick and then died after being shot repeatedly without noticing.

These are the things I really want to see in an updated survival mode. If not then I will just have to wait for mods that provides this.

I just want the Hard Core mode to be available on all difficulty levels. Not just the bullet sponge hard/very hard/survival levels.

I like most of these suggestions but fear bethesda isn't creative enough to do any of it. You'll likely require mods for this again and I'll have to hope said mods make the cut for me on PS4.

Options.

I want to be able to pick and choose what 'hardcoe' options I want to use.

I have absolutely ZERO interest in weapon durability and repair, it was a bad system in the last two games and I don't have confidence that IF they did re-implement it that Bethesda wouldn't just do it the same as before.

Same with respawning on death, I honestly would just reload last save regardless. So and I doubt Beth would bother anyway, again an option there. How would this mechanic even get explained in game anyway? That's primarily a Roguelike or MMO mechanic.

Eat, drink, sleep, I can get with, though I always felt it was a little broken in NV. I was literally having to eat every five minutes.

Bullet scarcity yes. Most of my ammo on my current playthrough has hit the 999 display limit on the HUD.

More dangerous Radiation. Already got a mod for it, so having it implemented properly would be nice.

edit: We'll probably just get eat, drink and sleep and that'll be it.

Yes, I am affraid Bethesda just will give us drinking, eating and sleeping. Worked well in New Vegas, I dont remember I had to eat every 5 minutes to silence character's hunger. Its still good move, they seem to be aware about F4's non-RPGness.

Considering one ingame day is, what, 24 minutes? It does feel like you have to eat too often if you require 2 meals and drinks a day. But I always play on half the timescale through console commands and in NV it changed accordingly. Felt much better.

Almost all the above are ideas which I agree with. I would add the following:

1. The ability to name settlers.

2. The ability to equip anyone with power armor just as I would any other type of armor. Give the order and they climb in- and stay in.

3. Brotherhood Knights, Paladins, and Vertibirds need to be much more resistant to small arms fire.

4. Badly wounded opponents should generally not be running and dodging at full speed and / or charging in for a point blank FTF resolution of combat.

5. Give the player the option to designate an individual as settlement leader and delegate tasks to him or her. The order in which tasks are done would be dependent on the order in which they're given to the leader. The player should not have to micromanage every settlement. "Build a wall", "grow crops", "build a trading post". When the player returns later, the assigned tasks may be fully or partially complete, depending on material and personnel availability.

6. The existence of automated turrets in any settlement should constitute a serious drain on said settlement's resource availability. The use ammunition and power, and this this should be reflected (the settlement sells resources in order to obtain the necessary ammunition; laser turrets should use power like water going through a floodgate).

7. Ammunition should have weight, and missile launchers should be heavier, very rarely scavenged and cost a small fortune to buy. In their quad format, they dust off Brotherhood vertibirds with remarkable ease. Power armor frames should be worth their weight in gold.

8. Power armor should be more expensive to purchase and much more difficult to scavenge. When a vertibird crashes, most of the PA pieces on Knights and paladins who rode it in should be destroyed and unavailable to be scavenged.

9. Companions can die.

10. Add at least one new assault rifle or carbine that doesn't weigh 20 lbs. and look as though it's water cooled.

Addenda:

11. It should be genuinely dark at night and far more difficult for any party to detect another. Meeting engagements should be a very real possibility.

12. An option to click off fast travel and a stat showing the number of times that a player's death sequence was initiated.

All I can hope for is radiation being more deadly and broken limbs needing splints or bandages. I have no actual interest in needs but since Bethesda added fun bonused to needs already I find myself using them enough as is.

Seems more like tedium mode rather then survival. Based on some of the things people want.

Eat/sleep/drink meters - Good lord, I felt like my character was a diabetic. It in no way added to the difficulty of the game, just the annoyance of having to go into my menu yet again, to eat some spam, or catch some sleep. I'd much rather have a system where you can only heal to say 75% total hp using stims, anything more requires food/drink or rest.

Crippled limbs - I actually like the feature in new vegas (needing to use med kits). The current crippling mechanic in fallout 4 goes pretty much unused. Having over 100+ stims, on the hardest setting saved without trying, is problematic in general though.

Broken weapons - Mixed about this, I generally like the idea, but how many of us ended up getting jury rigging as soon as possible? It seems to me that it is unlikely they will use their time on this feature.

Bladder...

I want to have to worry about self-relief...