An example I guess you can see in the BoS in a way.
In fallout 1 you have 4 major characters in the BoS who all represent major parts of the BoS, the Paladin who represents the militaristic side all order and tactics war and etc., the head scribe who represents the intelligence the research of technologies and the creation of new ones. cabbot just an initate who is enthusastic of the world and little knowledge of it partially due to the shelteredness of the BoS but also him being just an initiate, and the elder who draws from all three and that shows the brotherhood is a mixture not a singular archetype.
In NV you have Ramos who barely represents anything. You have a paladin who doesnt like the current elder so he angry. The scribes are essentially non-existent NPCs.
Most of the good parts are lent to the insanity and depravity of the elders, Veronica is just a dyke and same with Christine except Christine is angwy. The faction is simple as what the wasteland sees them as "A bunch of crazy tech people with issues."
If they all had a resurgence of their old tribal ways it would seem repetitive.I didnt mean resurgence but hints, or anything to deepen their character archetypes. The Chairmen really suffer from this and Benny doesn't really carry them at all because he feels like his own party. I can write a lot about the different factions and their goals and why they can/do exist, why they turned out the way they did, the people attracted to it, the people they make for fallout 1/2 (not all of them though) For NV it's a lot harder. As you said, and I agree, the NCR does that part well, the rest I think I'd disagree on.
