Took a half year break from the game and when I come back this discussion is still a thing? il chime in because I do think its an interesting discussion but I feel its a bit of a confusing one. I feel it comes down to this sentiment. 'The game needs 6 man parties, or it isent baldurs gate!' and I feel its flawed.
Baldurs gate 1 and 2 had 6 man parties. That very much is fact. However they also used the dnd 2nd edition rules set. It used THAC0 instead of AC. Rangers werent complete dogshit. The game wasent baldurs gate because it allowed to you to bring a 6 man party. What made bg1 and 2 what it was, was the setting and the story they told in that setting. The journey of the bhaalspawn that you followed. A story that is now very much a part of the canon and thats been told (and the bhaalspawn isent our PC but thats besides the point). The story might be continuation of it, or not. But at the end of the day the game is still baldurs gate.
Its a rpg telling a story in the forgotten realms in or near the city of baldurs gate. It uses the DnD rules set.
DnD has changed over the years. Bg 1 and 2 were based on a version of DnD that is very, VERY dated by now. The class balance is different, the setting has changed and the rules set has changed. Heck entire spells have changed or outright dissapeared from dnd since then. Same goes for class features. If they make the game to have 6-man parties it wont magicly be Baldurs gate. Nor is the game any less baldurs gate if it lacks 6 man parties.
However I am in favour of 6-man parties. As an option. Not by default.
Im a DM and a player in another group. Finding good encounter balance can be exceptionally hard. And dnd is written for parties of 3 to 4 players. You can have bigger parties but it quikly muddies the waters with regards to balance. It very easily becomes to easy or to hard if you muck that up. So giving us an option to do it would work imho. Maybe make it be tied to a higher difficulty or something or just place a warning that the game might be easier then it was intended to be. But more options for the player is rarely a bad thing and I couldnt totally stand behind the option of allowing 6 man parties.