SIGH. Through predictable given the recent UA.
Only way I'm getting that is if it's significantly different from previous editions of Ravenloft. Ravenloft is a pretty retrograde setting, with a lot of racist and some sexist tropes going on, as well some other "things that make you go hmmm" (and not in a good "horror" way), plus it's harking back to a kind of that was "for old people" when I was a teenager, and that your average 20-something today, probably has never seen anything of (Hammer horror particularly) and is only familiar with through sort of third-hand sources and recapitulations which also modify stuff (Japan does a lot with Gothic Horror, as has World of Warcraft).
But they could fix all that and update the setting I suppose, give us a more modern take on Ravenloft. Cut some of the less-interesting or effective domains (the quality varies widely), introduce some new domains, maybe shake things up a bit just generally, and that could be done without really damaging the better classic domains I think, because they're relatively discrete entities.
Given the recent UA my bet is very much on Ravenloft. Though I do wonder if there's even been enough time to get that UA into a book (maybe there has).
Innistrad doesn't do the Mist thing I think. Though it is weird that it's "The Mist Beckons" rather than "The Mists Beckon", because D&D conventionally uses the plural for the Mists I though.
