I believe we should have a combination of a weight based system, stacking system, and a slot system of today.
And here is how I would form it.
TLDR version: Slot system of today, Weight is determined by character stats/skill, and stacking is limited vary limited to things like apple juices, vary small magazines, arrows, not like guns, generators, clothing extra.
Wight system would be Stat/character determined, as a upgradable skill. And we can carry as much as 2.0 as the median of the skill. Equipped guns also factor into weight. More you carry, more encumbrance penalty. The skill itself would be fairly expensive to upgrade, but worthwhile!
Lets say everything is 100% speed until per say a mark (Lets not have a stiff gradient, I don’t want everyone dieting how much they carry for teeny bits of speed).
More encumbered (ties of encumbered) = less speed and stamina recovery. Later on more serious debuffs.
Tiers: Nothing (players should experience this for awhile) slight, moderate, then then heavy… And then crushing…
You can pick up as much as you want, but after a while it’s a serious thing. Like when heavily encumbered, your going much slower, and with side effects like your stamina does not regenerate anymore, melee attacks are weaker/hip fire worse. Mean, if your under crippling weight… Sure you can fight to full capacity?
And if you go extreme and deciding that you want to hold a crippling amount of weight perhaps you can even take physical damage, Pretty sure you can crush a person to death by stacking suitcases on them enough.
Anyway it allows people to trade there wellbeing for greed! Just think of some raiders with 5 miniguns in there packs suffering physical damage trying to get out of a clans vault area! Of course this point of pushing yourself should really be high to prevent annoying players.
How would you know your heavy? perhaps you could have a little line with a indicator of how encumbered you are under the stats panel in the bottom, with a green-red gradient, with several dots showing where each encumbrance stage is.
And then icons for heavy encumbrance (weight icon), and crushing encumbrance (bigger weight icon with a person below), just to help notify a player.
Important note: Buildables, logs, and scraps poses little to no weight, reason why is that when your building your base it won’t be a major hassle by forcing yourself to endure heavy weight just to get a decent amount of supplies. Mean, if you have five walls on you, do you want to be moving at 50% move speed?
All in all, Your physical strength determines how many pounds you can carry.
So just because your book bag can support 5 miniguns does not mean you should.
Stacking would be limited and constrictive. As in only a few items will stack.
Like juice boxes would stack 2x, same with the bars. This also changes the icon to show two boxes (as in one behind the other) in the menu. along with that show the median percentage of durability and amount present in the occupies squares of the main inventory. right click (menu of the specific item) will show specifics like which items are what percent, splitting options, ability to drag the desired item out of the stack (like drag the 100% juice out of the other 10% juices). Gives a option to select specific item in the stack.
What can stack? Arrows (to 6?), most pistol mags/vary small mags (x2, like colt mags),In the main inventory screen shows how many bullets there are in which mags like now, just side by side. Nails/notes/vary small multiple items or powders that could just pile (to 5?), vary small foods/drinks/items (juice, bars, sticks, books) to 2x, thinner items (wheat stacked upon wheat, boards of wood, fishing poles, pool cue, perhaps glass) 2x, extra. Nothing like stacking generators, windows, wardrobes, guns, most melee weapons, tools, clothes.
Just reasonable items. No, you cant stack pumpkins on top of pumpkins (since there bigger), But money? yes you can stack that! 10$ notes don’t need to take the same space of a timberwolf!
Small notes: Also shotgun shells automatically condense and “refill” there magazines/piles (unless encased by a container/mag). Same with other things, they condense where they can. nails when picked up don’t occupy new slots unless every stack is full/no other nails, and if you equip a holdable in a stack you hold the highest durability one.
Regardless that’s my idea and interoperation! Hope you like what I said and maybe you can improve upon it!!