Keep in mind that each of these NPCs will be playable characters with their own twists on the main plot; in that context, making them "special snowflakes" to one degree or another makes some sense. These are all potential main characters. Maybe it would be better if they weren't, but, well, Divinity 2 is what landed Larian this gig, you know?
That said, some "lesser" NPC companions' could be a great addition. comparatively simple, likable, and broad archetypes. A paladin who just likes to help people. A rogue who just likes money. A barbarian who just likes hitting things with an axe. Characters that aren't going to be driving the plot, but also aren't going to competing for the spotlight. Hell, if anything, that reflects actual D&D much better than every character having a deep, complex backstory. Some people love playing those kinds of characters; some are just there for the combat, or to try out a silly voice, or just get a sense of satisfaction from a nice, simple power fantasy.
I mean, Minsc and Boo were never destined to be the main characters of the original games, but that didn't stop them from being the most beloved ranger and hamster team in the world.
