I wonder if Crawford's world is one of thenew Settings they may be working on?Yeah, it's definitely not. Barovia and Borca are actually from the same world, and its established that after Barovia was subsumed, a couple hundred years passed and then Borca was taken too. Additionally, we actually know a bit about this world from Van Richten's. The city Malitain, where Ulmist Inquisitors originate, is from the same world as Borca/Barovia, and is notably not been subsumed by Ravenloft.
Not only is Malitain not in Toril (it's world is not named) people there seem to know the history of Borca/Barovia. So it seem more like that world is much like Eberron, where regions disappeared (like the Mournland).
It's heavily implied that Crawford's world is where Malitain sits.