It's exactly as plausible if not moreso than B5 or Star Trek's use of foreign cultures or dead customs, but with the exact opposite intent: They use those to distance us culturally and socially from the story; while BSG is using it to give us an immediacy to the narrative.
Use of foreign cultures or dead civilisations as a model is a quick and easy way of establishing a human or humanoid civilisation that is not the one we're living in. It fills in culture around an alien (either alien as in non-human or alien as in not western 21st century earth). It's not easy to invent a culture from scratch, there's too many variables to create.
I did'nt find the story any more imediate or gripping merely because the Presidential staff wore 21st Century suits. I had no issue with slightly retrograde technology, nor the military uniforms, both made sense. The suit and tie dress comes down from the eighteenth century, evolving and changing with fashion, would you be as happy with the costume had the shirt lapels been huge and kipper ties in evidence (even bow ties might have been ok as they appear a little otherworldy these days).
I'd conclude that it was a cop-out in the hopes of not chasing away people who might normally dislike Sci-fi. It's obvious the Sci-fi community liked it regardless, but did it work?