>random elements
i like it.
I replay those kidns of games mostly, so having some stuff change is nice.
The question is: if you play it with a non full PC party, wil the NPCs side agaisnt you? In OS2 that wasnt realy the case (or very easy to avoid)
IIRC in OS2 there are always 2 npcs that go against you, the ones that you do not choose. I wonder if it would be the same or if would be possible that you could have a "betrayal ending" like in "Lost Dimension" where all your companions are traitors and you discover it just when you are confronting the final boss.
Or the "final battle" is against your own traitor party? An ending worth of a game with full developement of game styles.

For examble: in single player your playstyle will confront or be similar to the other party characters you recruited during the game, and that playstyle could build the endgame and the final battle with your party characters for a common goal or against your party characters.
In mutiplayer it could be very interesting because of the spontaneous decisions in the last chapter of your real life friends. An examble: I play DoS2 over the last 3 years once in a year for a full week over offline lan with my best friends. We live thousands of miles depart and come together only for lan games in our old city of origin. The last three years we made it in DoS2 the first chapter completely together, while the second year we run over the map partly without knowing which quests the others solved already and the last year we fumbled together from books, stuff we found and quest log what we had to achieve to get the story forth. Maybe we will split in our game decisions some day or play together again the 4th year, who knows. But it would be worth a try in BG3, if this game had different endings for different party decisions, and maybe like in a real D&D P&P style the game master has to plan for a split of character decisions.