Please define for me "not being build around it". O_o
Simple as it is - it is the *intended* experience, crafted by the team. Larian chose this limit and the systems will be more or less revolving around it.
For example, GM4Him mentioned quite a lot that BG3 creatures don't follow "true" D&D stats, so it's reasonable to assume that Larian did not build their encounters around D&D challenge rating. Hence the most probable measuremnt - party size and expected levels of encounters. If we change party size then any kind of balance (which I think is in OK state currently, assuming it's the intended default difficulty) is thrown out of the window - 5-6ppl party will easily stomp through current content with much higher potential for removing enemies per turn or nuking high HP targets, and that also opens more class options which would provide more general flexibility for the party.
Can Larian make a setting for an optional 6ppl mode? Sure, and I'm pretty sure that's the easy part. Will it provide the intended experience that way? Nope, as the balance will swing heavily into players' favor, even if they were warned, and it's Larian who get blamed for an imbalanced mode even if it were players who asked for this. Then add difficulty settings and it's a whole another can of worms in regards to balance. Reception from players will vary a lot too and in case of further changes Larian might have a hard time finding what was truly overtuned or undertuned to fix. I would also say there's a good probability of DOS2-like event that will "seal" the party composition at one point (I wouldn't want that but that's something I expect nontheless) and I'm not sure how the game will react if there are more people left. Will the possibility be accounted for or will some scripts just break, etc?
it's nice to hear that they are trying to adjust the UI for people who want bigger parties though. And if there's to be a "proper" 6ppl mode... it will require a lot of work, which I've already mentioned. Maybe it could happen after release if demand will be high enough?
And I'm not really complaining, I'm just saying why I think it's unreasonable to expect a 4+ party size from the game. I would like an officially supported bigger party too as I think 4-man is a little too rigid but I don't see it happening. So even if 6 ppl will be supported by the game from a techinical point, you would probably still need a mod for this rather than an official setting.
