I guess I'm in the minority who enjoyed the trailer. I was struck by the inspired choice of Deliverance as the movie at the theater in Collinsport, given that it's a story of a group of outsiders coping with a society that they have trouble understanding.
I'd like to echo the thoughts of others about how appalling it is for people to argue over who is or is not a "real" fan. As the saying goes, beauty is in the eye of the beholder, and just because I may or may not like something doesn't make it wrong for others to feel differently. If this movie brings new fans to Dark Shadows and a fraction of them go back and watch the original series or the 1991 revival, I think that's a good thing. What's more, nothing that this movie does is going to change any of the prior art. If your preference is for the original series, it will continue to be available on DVD, streaming or whatever new medium becomes available. In fact, the restored versions of HODS and NODS may not have happened if not for this latest effort.
Maybe the best analogy is the Tolkien movies that Peter Jackson has made. There are plenty of Tolkien enthusiasts who are unhappy with the LOTR trilogy. The thing is, it introduced a whole new generation to Tolkien's works, who then can judge for themselves what they think of Jackson's movies. I guess I fail to see how that's ultimately a bad thing.
I will most definitely see the movie when it comes out. I seriously hope that it lives up to my expectations, and I hope that it is successful enough that it ultimately leads to additional movies. I would prefer to continue to hear stories of the Collins family rather than think that this could be their swan song.