I believe the topic was ethnicity; so let's be clear about what we are talking about.
There are very few races in the fallout universe. Human, Ghoul, Deathclaw, and a claim can be made for Supermutant.
But as far as ethnicity goes there exists the potential for an unlimited number of ethnicities. A cultural enclave is all that is necessary in order to create an ethnicity, and in a world as large as Fallout with isolated instances of civilization varied ethnicities should be popping up all over the place.
Once the issue of whether or not ethnicity will even be used is settled, the big question is whether or not the Fallout world would be better off with "real world" ethnicities or "made up" ethnicities unique to the Fallout world.
Wasteland had ethnicity as something someone could choose, and even though it had no effect on the gameplay at all (or at least as near as I could tell) the option existed: allowing for choices from Russian, US, Indian, Chinese, and Mexican as I recall. It wouldn't be hard to implement ethnicity as a reaction factor. And it would make the world more immersive. Truly people do react more favorably or unfavorably to other people based on their ethnicities.
The two "issues" which spring up when addressing the question of which type of ethnicity to go with "real life" or "made up" are a function of politics on the one hand and sociology on the other. If real life ethnicities are used allegations of "racism" would almost certainly be raised, and so the question becomes could Bethesda take the heat. On the other hand if "made up" ethnicities are used then the question becomes a matter of how do you justify the existence of these "new" cultures and determining in what ways the varied cultures interact with each other (definitely a much more involving and time-consuming procedure than the former).
With the idea of using ethnicities in mind I think the slider bar approach to "racial characteristics" to be time-consuming and stupid. The game should have a basic depiction for each ethnicity with separate looks for male and female. That way those of us who aren't interested in spending 2 hours contorting a face to try and get something close to what we want, only to restart because we find that the look is different in game than it is in the character creation process DON'T HAVE TO! I'm not against the inclusion of an option to manually alter a character's appearance for those people who do want to create a unique looking character, but this should be for purely aesthetic purposes, having no game play consequence what-so-ever.
Another reason why the "slider bar" approach would have problems with Fallout is the existence of traits like "small frame" and "bruiser." These traits affect body size, shape, etc. So in the world of Fallout you really shouldn't have control over those features; it should be a matter of whether or not your character possesses these traits. I certainly don't want the possibility of a fat man with the "small frame" trait to exist.