I remember the first time playing the game - first there was this elder, that did not want any newcomers. And I tried really hard for him to change his mind (I could make you care) but this went wrong. Then I tried to do things for him (Still in the dark) and I stumbled upon a posibility of changing the elder. So I did.
And there it was, the most unexpected thing happened - the new elder said: "Yup, you did soooo many things for us that you probably expect an uber reward. We don't have that kind of stuff, so I am now officially declaring you a member, or wait, even better, a paladin!"
Why a paladin?! I'ma an obvious scribe, and if they have no vacancies there (which is not the case, cause hello - there are no schools there in the postapocalyptinc world and I'm like way overeducated) I'd be an excellent knight (cause my skills are better then most of the NPCs labeled as knights in Hidden Valley), but I'm certainly no Paladin.
What I'd expect in that point was to become an initiate. That would be like awesome. One does not become a Paladin of the Brotherhood just like that, it takes years to train and learn the ways of the Brotherhood. How am I representing the Brotherhood if I actually don't know a thing about the guys.
I'm trying to explain here why I think the Paladin nomination there was an incredibly underdeveloped point of the story. In my understanding they (developers) went for Paladin so that no further quests requirements were neccessary while being a member.