Unfortunately, they dumbed down Vicki once Barnabas showed up. She started out as the plucky heroine in distress, trying to learn her identity (remember how she went up to Burke's apartment because he said he had the private detective's report there?), and somewhere along the way, lost her pluck. It's a shame, too, 'cause Vicki really was pretty intelligent when we first met her. I always thought once she had her first experience with a ghost (Bill Malloy), she kind of lost it, mentally, and was never really the same afterwards.
Still, I liked Vicki a lot in the first couple of storylines, and always hoped they would reveal who her parents were, since that was the driving force of the show when it first came on. It was a huge oversight not to clue us in, but there certainly have been enough fan fic stories written speculating upon it, and that's a good thing--you can provide any ending you want.
I don't know why Vicki couldn't have been an intelligent damsel in distress, but I think in Dan Curtis' warped mind, intelligence and beauty really did not go hand in hand and mututally excluded each other, at least in the show's heroines.
I have to confess that I DID grow annoyed at Vicki for not picking up on where she was and what had happened to her to the degree that she shut her mouth about how everyone looked like someone she knew. I gave her credit for more intelligence than that. However, Barnabas' arrival started the dumbing down of Vicki to the point that even Alexandra Moltke couldn't stand her character anymore.
Love, Robin