I dont feel you assesment of the BG1 cast is accurate though. Basicly every single one of them is a 'snowflake' by your metrics as well; but you dont go into that if you oversimplify them.

-Imoen 'just' beeing a Bhaalspawn for example. Ah yes, because most of the people that I know are the children of literal gods. Are you kidding me?
-Khalid and Jaheira beeing Harpers is also pretty much a big thing. You dont see it ingame but the Harpers are a major political faction, and theyre quite well known Harpers at that. In BG2 that also bites Jaheira in the ass. I wont spoil why if people havent seen that yet (go play BG1 and BG2 Enhanced editions. They are still very good games and worth it!)
-Minsc is more of a joke character and not that outerworldy. If you ignore his monstrous strength and the fact that he has beserk rage, which at the dnd edition that the games were made off made him unique. Or if you ignore Boo. And you shouldnt. Boo is awesome!
-Montaron and Xzar. You think some of the characters in BG III are obviously evil? They dont come even close to these 2 unhinged maniacs.

Lets go into some more characters though for good measure:
-Viconia. A female drow. On the surface world. Yeah no special secret or whatnot but this alone makes her an rarity. And she also doesent seem to want to kill every man she meets (even though she does think them inferior) which also makes somewhat of a rarity in drow society. Yeah nothing special to see here
-Branwen. When you find her she has literally been petrified for god knows how long and she comes from some far off culture. Shes no living bomb but an oddity on the sword coast just the same. Her different tongue compared to the locals is kinda funny.
-Edwin. Powerfull red wizard of Thay. Nothing that special about him, to be fair, if you want ignore just how powerfull he can be in BG II.
-Xan. An Elf from from some politcal faction (cant recall) send to investigate the Nashkel mines. Has a Moonblade. A fricking Moonblade. When you find him hes like lvl 2 or lvl 3. Sure, mages dont WANT to be in melee but how many people do you find who have literal legendary magical weapons just on their person?


While I agree that Laian makes their characters.... Unique in some other manners its not like the cast of BG1 and BG2 were the avarage folk either. Some were major parties in local political factions, had ungodly high stats (like minsc, if you take into consideration that a S of 10 is avarage he has a nasty punch!), were offspring of gods or otherwise had powerfull connections/artifacts that mark them as very exceptional individuals.

I could go over BG II companions as well if you wish by OP only mentioned BG I for comparison.

TLDR: BG1's companions most defenitly were not bland and stale. Alot had backstories or remarkable gear that set them apart from normal indivuals. Sure, not all of them were living bombs or whatnot but by BG 1's metrics they arent that remarkable imo. Your (likely) party in BG 1's early game was made of 2 god spawns. 2 harpers and 1 or 2 other individuals who were quite remarkable in their own way.