if they had made it, it would've been the original, non-time-travel story sans Vicki.
The likely scenario would have probably been the original timeline. Though it might have been an interesting twist if, say, somehow Maggie (there apparently being no Vicki in the hoDS universe) was somehow transported to the past and she was able to prevent Barnabas from being cursed, thereby undoing all the events of hoDS. Though I suppose that wouldn't have been what DC would have wanted because if he did a Barnabas sequel, he probably would have wanted to try to outdo the vampire blood and gore of hoDS, sacrificing even more character moments in the process.
Plus, if Frid would have been willing to continue to play Barnabas, and if DC would have been willing to do more than two DS films, in all likelihood MGM and DC would have wanted to be able to feature vampire Barnabas in as many sequels as possible.