It won't happen. The game's bones/core is essentially done at this point. Larian wouldn't market Early Access where core game features can be altered. They have built this game for a party of four and that's what we are getting.
Very sadly, I have to agree. And it's not just that they have essentially finished core development of the game. It is also Larian's/Swen's "vision" for the game. That vision is something they very firmly believe to be awesome, so why would they change any part of it? I, and some others like me, however, consider that vision to be utterly stupid and ridiculous. But Larian is not going to give us the game we want. They couldn't care less about the game we want. And over time I have degectedly come to accept this reality. The only possible salvation of this game for me is if there exists a modder out there with the skills, time, and willingness to literally take an axe to the game, and remake the game as a true D&D and BG game by rebuilding many of its systems. Then and only then will this game be a halfway decent game for me.