I don't mind the redundancy of this thread, it just allows me to try and distill my feelings through repetition heheh.
The main reason I would like to see a full party of 6, is so that this game will feel more like Baldur's Gate, which was one of my all time favorite games! Not Jade Empire or NWN or Kotor or Dragon Age or Mass Effect, and not Divinity Original Sin or Divinity Original Sin 2. But Baldur's Gate. I think if they increased the default party size from 4 to 6, the game would instantly feel more like a proper Baldur's Gate sequel and settle the waters on that point. The gameplay would then be differentiated from their previous Divinity titles, and I think it would just be a nice nod to the BG lineage.
In the Gold Box games it was a party of 6-8, plus 2 additional NPCs Baldur's Gate 1/2 was a party of 6 and up, since it also allowed for follower NPCs and various character summons at different points.
The games which came out later, and which went with a single AI Henchmen or a Party of 2, 3 or 4, just feel like they are coming from a different lineage to me. One that maybe still starts with old bioware dungeons and dragons style RPGS, but just not the one that I'm into, which is Baldur's Gate hehe. I mean that's why I'm here, that's what I signed up for.
It just seems like a very simple way, using systems already in place, to capture more of the spirit of Baldur's Gate. So that's my main reasoning, I have others, but that's the most important. Its to capture a "feel" more than anything else, one that BG3 is currently lacking for me.
So its sentimentality then? I would invite you to consider that sentimentality is not a good reason to do...well....anything really. And hey its a video game - no big deal - its not like you are making a major life choice based on sentimental reasons.
Still - I recall some guy spouting off that if "BG3 didn't have the Naskell Mines then it wasn't BG3". In fact, most of the major early negative reactions to bg3 - amusingly made fun of in this video by Mr. Narbs - was based on this sort of sentimental knee-jerk reaction to the announcement of the game not being made by Bioware or that it was not using the infinity engine.
This is what happens when you elevate "emotional idealism" as being a virtue. It used to be we had a society that - properly - looked down on excess sentimentality as being a negative character trait. I'm old.
And listen, you will likely get your 6 person party - someone will mod it in. I doubt Larian will do it, as they have balanced the game for 4 people plus random allies and I don't see them moving on this one. To go back at this point will add excess development time as they would need to rebalance. Also they are a forward thinking bunch - there is a reason they get a lot of credit for moving the genre forward by leaps and bounds - and to do that you need to let go of the past.
However, I would invite you to explore this 'sentimental-thinking' and make sure you are not using it excessively in your decision making. It can be very destructive.