In the Maggie Kidnapping story, Dr. Woodard refers to Dr. Hoffman as a man. The intent was to have Hoffman discover Barnabas and Barnabas would eventually kill him (probably after his cure failed). Burke and Dr. Woodard most likely would have staked Barnabas following that. Perhaps, due to the appearance of Sarah, they originally intended Barnabas' spirit to reunite with Sarah and be at peace.
There are times where Burke is on to Barnabas (he sees him enter the old house at dawn and not leave, he hears the music box in relation to Maggie telling him about a "soft, tinkling sound" in her mind). At this point, the Seaview Cottage plot is briefly introduced, which could have been a follow up story after Barnabas is killed.
When they had Grayson Hall cast as Julia Hoffman in place of the male Hoffman, it looks like they were going on as originally planned. When Willie is blamed for Maggie's kidnapping, the story change was probably made and the Seaview plot discarded as well as the death Of Dr. Hoffman (and probably Willie too).
They had to kill off Barnabas' protaganists (Burke and Dr. Woodard) for him to remain on the show. A total reversal of what they originally intended.
A male Dr. Hoffman would either:
a.) Been an end to the Barnabas story
b.) have Barnabas still kill him and Barnabas would remain on the show...though alone with no one else to help him. This may have led to the addition of yet another new character for him to play off against
