mythago
Hero
Well, people who like classic Ravenloft (and Universal Horror and Hammer Horror) will be cool with Ravenloft, but people accustomed to horror as defined by movies since 2000 will not think it qualifies as horror until someone is butt-raped by a running chainsaw. If it does not strike that note, then many will say it is not horror.
Not sure why, given that slasher and gore flicks were at their most popular well before 2000. Even the Saw films, at least the early ones, had a veneer of psychological horror, and I would guess that the young'uns are more likely to have watched The Blair Witch Project than Friday the 13th or Texas Chainsaw Massacre. Not to say that there isn't gore out there, but personally doubt it's as simple as Kids Today preferring gore over subtlety.
That aside, I suspect the problem is that many of the tropes of classic horror, like ghosts, vampires and werewolves, have been used far out of their original context as horror - it's hard to make Strahd quite as scary in a culture where vampires and werewolves are sexy brooding guys who fight with their shirts off, or are noble antiheroes.