I think those among us who feel as you do, picard, that the only acceptable new version of DS would be one as closely identical as possible, are in for much disappointment.
Consider it this way.....the original Dark Shadows already exists. It was created and produced and it exists in a permanent state. Thanks to the marvels of modern technology, it will shortly be available in its entirety for anyone who cares to spend the money to own it. You can then watch it, in its perfect original state, any time you wish, exactly as it was.
That being the case.....why on earth would anyone attempt to RE-CREATE what already exists?
To begin with, it's impossible.....all the original performers, writers, crew and what-all are either dead or too elderly to perform their original roles. Time doesn't stand still for anyone....nor does it run backward.
That being so, why should a new production not take a new direction? It could be a re-telling of the original story in a new form.....or it could be a "next generation" approach.....or it could be an infinite number of "other" things, limited only by what the new production staff choses.
They might choose to be reverent towards the original, please all the old fans, and create no new fans at all. Or they might chose to ignore the old fans, and find a new audience with a very different version of the story. Either choice limits their chance at a successful run. So it's reasonable to assume they will choose to find a middle ground that will somewhat satisfy older fans, and hopefully intrigue new ones.
No matter what....the original still exists. It won't be in any way diminished or changed, no matter what comes next. And if that 's the only version you ever want to see....why then, you have no need ever to watch a new one at all.