Given the nature of the show, which has a lot of mystery and suspense with cliffhanger endings, if they repeat the same story, they would lose almost all of the initial "built-in" audience.
There isn't a "built in" audience - existing fans might number 50,000 at a very generous estimate... Fine to keep an old entity alive, but not very much for a new show that needs an audience of millions to survive.
While from the casting it would seem that it's the same basic situation, I would have to assume that they've come up with some drastic story changes.
This is just my opinion but I would like think there are probably several million fans that constitute Dark Shadows' fan base. I do not think if DCP told the WB that its loyal audience consisted of only 50,000 individuals, that they would have gotten to first base on this project. I remember reading somewhere that the WB was initially impressed with DS's large fan based-franchise.
I did see on imdb that he's from Scotland and -- O.T. -- Geraint Wyn-Davies is originally from Wales but his family moved to Canada ... wonder what's with all the "Celtic" vampires ... I admit I generally think of vampires as dark and brooding, but it's best not to stereotype people ...
This is just my opinion but I would like think there are probably several million fans that constitute Dark Shadows' fan base. I do not think if DCP told the WB that its loyal audience consisted of only 50,000 individuals, that they would have gotten to first base on this project.