I'll chip in with my two cents I suppose, been wanting to make an account for a while to comment anyway. I will say, I personally didn't enjoy DOS2's story (I did, however, enjoy the battle system enough to grin and bear it) while BGIII already feels leaps and bounds more interesting narratively. I also played the game after the third patch, so that might affect my opinion vs yours.
Larian doesn't seem to care about the story, or at least doesn't seem to care about the story enough for a game at this scale. I don't think it's (necessarily) bad writing, I don't think it's a bug issue (more on that later), I think that Larian simply prefers to give us as many RP choices as possible no matter how much harm it (potentially) creates for the story's cohesiveness and immersion.
I think they care quite a bit. A lot of what they're attempting feels fairly ambitious. That said, I do agree that trying to provide absolute freedom to the player is the antithesis of well-written narrative. You have to impose boundaries.
It is a bug only if there is a conversation that is not triggered. I doubt such a conversation exists.
A lot of them strike me as bugs. For example, I've now played through the game several times, and when Nettie tries to poison you, she'll address either Shadowheart or Lae'zel and ask them to leave (they'll refuse, which is why they're my ride or dies, fuck the haters). However, there have been times when this exchange wouldn't trigger. I believe Larian has also mentioned they're going to implement companions interjecting for specific skill checks. I did find the Astarion example egregious, but that's the only time in the game where a companion didn't react at all to a situation that surely could've used a reaction for me. That said, it does seem like the game prioritizes only showcasing one companions opinion in a scene and picks which companion reacts seemingly at random (perhaps it's tied to approval? I'm uncertain).
3. Restrict the raging player - too much choice that doesn't mean anything is not worth it. the most coherent part of the game from a narrative point of view is the tutorial area, where you can only move forward. I'm not saying make the game linear, but either address the fact the player is doing things out of order, or don't let him do it. Even Baldur's Gate 1, which was anything but linear, had certain places blocked for you until you reached a certain stage in the game (like the city itself for instance). the situation in BG is built like you have access to chapter 3 of BG1 before you arrived Neeshkal. How can you build a narrative around the goblin threat if you can go to their fort and kill all of them before reaching the druid grove? again, you could try to address it (option 2 in this part), but as long as you have so much freedom to do whatever you want, it is very hard to create a story that is not all over the place.
I would love to hear your thoughts and ideas as well.
'Too much choice that doesn't mean anything' is relative. I like the little details such as more lax answers leading to Zevlor punching that one mercenary, while more uptight answers lead to Zevlor getting punched (unless you mediate the dispute). I like that the Drow have an easier time getting into the goblin camp. And above all else, I like that the option to bypass dice roles exists, constantly tempting the player. It's the thesis of Baldur's Gate regarding power/abuse of power.
And I disagree that the most coherent narrative is the tutorial. All of the major sidequests dovetail back into the main tadpole conflict in some way or another. Wyll, goblin camp. Lae'zel, Risen Road. Astarion, bog. And each sidequest also furthers specific companion quests. Not only that, but most of the companions personal quests all seem to tie into the main overarching plot (Shar worshippers, cambions such as Mizora, Netherese magic, and the Githyanki/Mind Flayer conflicts are all involved in the Absolute conspiracy).
Shadowheart and Gale are a little less defined, however. Although Gale, from what I understand, was a last minute addition and originally planned to show up later in the story. It IS fairly easy to miss out on the narrative, however--I missed the broken down Selune statue SH reacts to (in the Blighted Village) in my first few playthroughs of the game. And Gale's personal quest is really hard to trigger too. I'd say that's more an issue of game design (and the nature of EA), however, not narrative flaw, since the narrative itself exists and is quite interesting. As opposed to DoS2, where regardless of whether it worked properly or not, I just... didn't care.
As for the whole companions/origin thing, I'm indifferent to it. It's certainly a concept I wouldn't mind seeing iterated upon, so if Larian can continue to improve it then more power to them.
Perhaps one way to ensure party members are involved in their personal quest (or at least Wyll's, as you miss out on a LOT if you don't bring him along, although I did find his tantrum at being left behind hilarious) would be some sort of gather your party function similar to what DA did, with Wyll as a mandatory party member for that segment. I can certainly see this being annoying for a subset of players, but we're both in agreement that restrictions can be good, so it's certainly worth considering at the very least.
The goblin camp is being treated as the only way to progress the main story because the other two options currently aren't available. Lae'zel's creche questline is clearly unfinished (all roads will end at Moonrise Tower, however). I know Halsin says we can't progress into the shadow area but Halsin is an idiot so I don't take that too seriously.
My biggest gripe so far is the progression of time, personally, as well as the fact that so many events/companion moments are tied to camping. It's one of those non-digetic gaming concepts that really takes me out of the story. I don't care if we get a day/night cycle, but the fact you can fuck off for an indeterminate length of time without the Grove closing off is absurd. It also completely undermines the urgency of getting your tadpole removed, although since this is a plot point I'm not as bothered by it as I am by the Rite of Thorns seemingly never happening while I spend a week fucking around with gnolls and githyanki and zhent. Some sort of timer, maybe? I know events auto-complete after a certain point, but it makes more sense to me to tie it to how often you long rest.