For the record if this thread exists at all is precisely because both Swen on twitter some time ago and another Larian guy yesterday on reddit said explicitly that while this is what they are going for now, a 4-men party is NOT set in stone yet.
I admire your optimism.
Anyway, the combat system wasn't set in stone either, until we read the interview with Swen, where he admitted that they wanted to make a turn-based game since day one (but obviously just kept it a secret in an attempt to not upset the "stupid Baldur's Gate fans".
).
This is obviously already set in stone and it won't change, because 1.) "Baldur's Gate 3" is a D:OS clone and 2.) combat would drag on way too long, as turn-based combat is slower than your grandma. In Baldur's Gate you can mow down a swarm of Gibberlings in seconds, in a hypothetical turn-based mode it would probably take a few minutes - and you could even make a nice sandwich in the kitchen while waiting for the Gibberlings to finally end their turn.
Like I wrote, I admire your optimism, but you'd probably be better off just accepting that "BG3" will not have a party size of six.
