I'm not sure about this as I'm not up on all the other soap ingenues, but I think most of them had family in their stories.
Tara Martin had a father, a brother, and another brother who went upstairs one day and disappeared never to reappear again. Everyone in the entire town had group amnesia; no one remembered that he had ever been born. So, Vicki is the only orphan among the ingenues, and she comes to a new town, instead of being a current resident like most of the other young heroines were.
I think that the way the story was originally to have gone; we would have learned more about Vicki. We would have seen her involved in the decision of which guy to fall in love with, the wealthy Burke, or the handsome lawyer, Garner. (I never saw these early episodes, but I hope to someday.) We would have found out who her parents were too.
Then if they had decided from the beginning that Barnabas was to have been a long term character, I'm sure he would have pursued Vicki from the get to, not Maggie. The writers would probably have used him in a new love triangle with whichever of the two handsome hunks won the first contest.
This is just my opinion of course, but there you have it.
I think that after Barnabas became the new leading character; the writers abandoned the Vicki mysteries, she then became the character that we were destined never to know anything about.