Any fan that doesn't embrace this movie, even if it is with reservations, is off their rocker. It'll most definitely bring in new fans to the DS lore and legacy, and will undoubtedly increase the potential for future projects of a DS nature. I know that it will be hotly debated before and after its release (it already has been) and that some people will absolutely hate it. But that's a fandom for you: some love it, others hate it. Its never all in one category.
One thing I am fearful of, however, is audience pandering. Others have already spoken about this. I just don't want it to be suped up with drama, action, and special effects to please today's target audience. I have no doubt that at least one of those things will be heightened anyway, but hopefully its not something that will bring down the film. Let's face it, a slow-building, thematic film is not popular these days.
Oh, and the other thing I have nightmares about is having to eventually hear that "Johnny Depp is the first Barnabas Collins." Oh. The. Horror.