I can agree with some or many of these complaints. But not all.
6) Equipped weapons are carried very strangely, they seem to be attached to the back by some force field. How does that work? Also it is very impractical. Why not have swords in scabbards, arrows in quivers, and longer weapons carried in hands? The only one that carries a weapon in hand now is my Tav. She has acquired a flaming sword and insists on carrying the flaming end in her bare left hand.
This problem has been with videogames from the beginning and it's not going to be solved in this one either - not when you have a ton of actions you need to peform while wearing a ton of weapons which you also need to mesh with a ton of different body types AND with a ton of different possible armors and clothing including underwear. It is simply impossible for the modellers to make the amount of possible permutations all look right.
9) Characters carry an enormous volume of stuff that would need a full shipping container in reality. But no one even carries a small handbag.
True to the tabletop version as well. Weight and inventory space is an abstraction in games. Even Solasta, which has pretty stringent limits on the amount you can carry allows for you to stash a ridiculous amount. The game would be less fun if you had "realistic" weight limits.
10) Defeated enemies stay dead, but party members are very easily resurrected.
Game.
12) The option to send items to camp is utterly ridiculous. Or at least some kind of explanation should be given. And the option should not be available when no camp has been established. And again the playing field is not level. Why don't enemies send stuff to their camp? For example, the goblins that have found the druid's grove could write a note and send that note to their camp.
Have you heard of the idea of "Anti-Frustration Features"? Lots of games do little things which are not realistic, but are done because this is a freaking game and games are supposed to be fun. The less tedious busywork you have to do which adds no interest in a game, the better.
13) The limitation of 4 per party does not make sense in the game. A fifth can not join, saying you're full. How does that make sense? I understand the need for gaming mechanics, but please try to make them sensible in the game world.
I would like at least 5 people in the party as well, but that's not likely to happen. What is your suggestion for "make them sensible in the game world"?
14) Short rests are very strange: how can you fully heal by standing still for less than a second?
Game. Time doesn't pass in the game. Do you want to wait around a real-time hour for the rest to complete? I doubt it.
16) When zoomed out, the camera is able to show a lot of the game world. Much more than the playable characters could see in reality. It would be nice to have a first person view during exploration, and switch to overhead view during combat. And maybe faraway landscapes and objects could be made more hazy? Also the mini map shows info on charcters that are not in the line of sight.
That will still mean needing to add a lot more stuff to the map for those "hazy, faraway landscapes", or expanding the map sizes to accamodate the far-away stuff. Maps can only be of a certain size to avoid causing performance problems. Lag isn't very immersive either.
17) Given the various personalities of companions, and the urgency of the tadpole problem, it does not make sense for them to hang around the campsite doing nothing while a party of 4 goes exploring. Can they be performing other tasks somehow? Hunting and foraging perhaps? Or be recovering from wounds?
Not a terrible idea to make use of other companions for foraging and such, but what wounds? Even if wounds were a thing - which they aren't, not even in the tabletop - there's no guarantee that they'll have wounds?
I think two immersion problems could be solved in a single stroke: Have the party travel with a cart that is pulled by horses for example. The cart can carry all equipment and it allows a camp to be set up at safe locations. Of course the cart can not enter dungeons, so it will not be possible to loot 20 goblin shields from a dungeon without some serious running back and forth. But I don't think I would miss that. It is entirely reasonable to loot only gold and jewels from a dungeon.
Stil, a more permanent camp would probably be needed for the inactive characters to reside.
You talk about immersion, but where did the party get a horse and cart from? Would they have it on the beach at the start? Do we need to watch the horse and cart move all the time? Will monsters be able to kill the horse?
There is a limit to how much realism can be put into game, and much of what you're asking for would add tedium for no gameplay benefit.
I will say that Solasta did have its own way of discouraging "20 goblin shields" by having strict weight limits and long travel - with random encounters - between places. But even that game did acknowledge players urge to maximize their income by collecting everything not nailed down, and they introduced a "Scavengers" faction which picks up all the loot you didn't take from dungeons you cleared and giving you the option to take any interesting bits you want from what was collected, and take a portion of the rest as income. That obviously won't work for BG 3, but the fact that they felt the need to put in that system acknowledges players will want to take it all.
I can understand why it can be fun to hoard stuff and maximize the amount of gold on your savings account. It is basic human psychology. But on the other hand, dealing with limitations, serious setbacks and difficult choices can also be very rewarding in a computer game. The bigger the losses you sometimes have to take (for example: not being able to drag heavy valuables out of a dungeon before it collapses), the more rewarding your successes will feel. That's also basic human psychology, I think.
I have fond memories of playing XCOM games in iron man mode, where party members would remain dead if they died and you had no option to load a saved game to bring them back to life. Those setbacks and defeats really hurt, but made the victory in the end all the sweeter, and the experience more memorable.
It does not make a lick of sense to bring up XCOM in this context, that's a completely different type of game with a completely different type of mindset behind it.
Not everyone likes playing one-shot, die-and-restart-from-the-beginning games. The Rogue-like/Rogue-lite genre tends to have short simple gameplay loop. Not a 100+ hour long game. Not a lot of people want to get to hour 89, have a party wipe and need to go back to the start, seeing 89 hours of the same content again just to get back to the 11 hours of new stuff.