Well, 'alienated' is probably a strong word to use. A lot of 2e Ravenloft fans (I'm talking about the diehard types over at fraternityofshadows.com who've been keeping Ravenloft alive, releasing large and generally high-quality netbooks, etc etc since 3rd ed) REALLY disliked the new take on the setting (I count myself among them, for what it's worth), but only the really hardcore can't find anything worth borrowing/appropriating etc in the new edition. As far as i can tell, general opinion is that the new Ravenloft baby is cute at times, but that still doesn't mean you had to so ruthlessly throw the old one out with the bathwater. A very casual skim over there says that most people take bits and pieces from VRGtR and just throw out the whole floating domains concept and run it in some version of the Core. And its worth noting, the posters on that board disproportionately represent the people who really liked the 2e/3e Ravenloft. I've seen a lot of posters here who say that they never enjoyed the old Ravenloft but did get interested in VRGtR.
But still, disliking the creative choices in one product (two, if you count Curse of Strahd) doesn't mean that the older school fans are actually alienated as such - they may very well buy other WotC products from here on in. After all, from WotCs point of view, if a group of fans feel alienated and decide to avoid WotCs take on Ravenloft in future - so what? It's not like WotC is going to release another Ravenloft product for them to boycott any time soon.