I appreciate you taking the time to address all of these components of these game. I'm just gonna comment on a few of your points that would be most important to me.
1) Food
I very much agree with you that food should not be consumed in combat, as this makes food function just like health potions. I don't agree with the food buff idea however, because it would essentially turn food into a magic potion or spell by another name. Our attributes like Wisdom or Intellect are hugely important, and even increasing one by a small amount has a large impact on the bounded accuracy system of 5e. Adding another buff to players would reduce the relative importance of class abilities/spells, magic items, and the potions we consume, and make food way too important a feature in the game. Not to mention encounters would need to be made more difficult so the content isn't trivialized by the added power.
I actually think food is too powerful as it stands, even if it couldn't be consumed during combat. Currently, it already invalidates numerous class spells and abilities, such as "prayer of healing" for example, which heal players when out of combat. Why would a cleric waste a spell slot to heal their party members out of combat, when the party could just eat the overly abundant food offerings to heal to full every time.
I think players should only be allowed to benefit from a certain number of food items per day, and only while outside of combat. As players level, they will prioritize keeping higher quality food with them to make each use count. This also creates more player choice and strategy, to decide when it is worth it to restore health out of combat, rather than mindlessly auto healing to full after any damage is taken. Higher quality food should be rarer, so that the common items like apples would still be used at times when the player doesn't suspect as much need for healing before the end of the day, since they want to preserve the good stuff for more important moments.
However, even if these changes were made, the players still have way too many resources at their disposal, which speaks to another point you made.
2) Camp
I totally agree, using a long rest should come with story consequences so as to dissuade its constant use. The fact that players enter every encounter in the best possible condition makes the game less fun, and too easy. These consequence could relate to the condition of our tadpole, or how certain events unfold in the world. This would force players to choose when they think it is worth it to fully restore themselves, rather than take long rests for granted and using them after every minor event.
For example *spoilers*, with Auntie Ethel. If you talk with Auntie Ethel and Mayrina in the cottage, but choose to take a long rest after you speak with them, Marina can no longer be saved, as Auntie Ethel has already sent her away to one of the other Hags in her coven. Therefore, once the Auntie Ethel encounter has been triggered, you must defeat Auntie Ethel before taking a long rest, or you lose the ability to rescue Marina. The player must ration their resources through the different layers of Auntie Ethel's hideout, or they will suffer the story consequences that accompany their decision to take their sweet time while on a rescue mission. Perhaps dialogue would be added to the initial conversation with Auntie Ethel, so that first time players are given a hint that this is a time sensitive encounter.
This preserves player choice, where for example, players become too injured after fighting Auntie Ethel's servants, and therefore decide it would be better not to chance the Auntie Ethel fight without recovering first, even if it means losing Mayrina. It also increases the value players will place on their abilities, and increase the value of using strategy while in combat.
Currently, I often find myself indifferent to most consequences I suffer from fights, due to the knowledge that my characters will be completely restored as soon as the fight ends. As long as my characters have at least 1 health after each fight, it makes no difference how much damage they took, or how many abilities/spells they used, etc. The changes to both food and long rest would help change that for the better.
3) Weight System
I personally prefer the weight rule as implemented, although there are magic items in DnD such as a portable whole, bag of holding, or Heward's Handy Haversack, that allows you to carry a fixed amount of extra item weight at a drastically reduced cost. I think it would make sense if our characters found some of these items, but they should be rare and meaningful. Otherwise, I think it makes sense for our characters to store items we don't plan to use regularly at camp, and spread important items across the party. I think regular bags could be useful to help organize our inventory, which can become quite a mess, but shouldn't reduce the weight burden of items stored in them.
