Playing Arcanum with an idiot evil half orc was a great game experiance.
But I agree that 8 int is not an idiot and the game has so many skill checks that your stats and skills matter.
My main issue was that some players ( well, at least I did ) will always use the char with the highest cha to talk to others. Better prizes in shops and higher chances to convince them.
So I almost never controlled my own char outside of combat.
D:OS2 and BG3 do not have a main char, all party members are equal. On one side I can understand that NPC interact with all party members equally because they see only a group of adventurers.
On the other side it can make your own hand crafted hero feel les importent.
Well, I play this game as single player with a custom char and companions.
Some things seem strange to me because D:OS and BG3 are designed for single player and multi player at once, like no real pause button (well, now you can go turn based) and NPC repeat all their lines again when you talk to them with a different char. (dammit, I just want to sell my junk and you tell me your whole life again).
Thats why i still love the idea of the party as a whole doing the conversations. Like with skill, class and race etc. options we simply get the option to have another partymember answer ([Astarion][Rogue]: "....."). It would stop feeling like the others chars are just simply standing around ignoring what is said, even when they actually could contribute to the conversation.
For trader pricing either take the highest cha or use a middle of all cha/2 or something like that.