Brighter Points of Light. Any large town in the “official lore” is probably at least a small city in my version of the setting. Additionally, the landscape is dotted with many villages, farmsteads, and towns not detailed on conventional maps of the setting. There are more inhabitants in Ravenloft and consequently more institutions of note. For example, the city of Ludendorf in Lamordia is home to the acclaimed Ludendorf University, a college focused on the sciences and natural philosophy. Ingenious scholar teach there—though they are shadowed by rumors of dark, inhumane experiments. (Note: By breaking Ravenloft's "Core" into a bunch of islands floating in the mists, it seems likely that the new version of Ravenloft won't quite adopt this the way I'd prefer.)
The Seas are Harsh Mistresses. The Nocturnal Sea and the Sea of Sorrows are both dangerous, but they can be traversed reliably and are central in connecting the civilized lands through trade. Persistent mistways—passages through the mists that form the boundary of the known seas—allow for more frequent visits to otherwise isolated island domains. Knowledge of the mistways is carefully guarded by captains and navigators who wish to have a monopoly on trade with those lands. (Note: it's unclear to me right now, but it seems like sea travel and interconnection between domains is being downplayed in Van Richten's Guide to Ravenloft.)
A Land of Strange Visitors. Because strangers from other worlds are often pulled into Ravenloft by the mists, the people of Ravenloft are more used to—and more accepting of—encountering a wider variety of folk. Although they may be rare, any race or ancestry can be found in the land. Strangers bring their cultures, factions, and religions with them—some of which will have taken root in Ravenloft to become new institutions on foreign soil. (Note: I suspect this will be the standard in the new Ravenloft, actually. WotC must know that now is not the moment to explore "fantasy racism" again in the setting.)
Haunted by Evil. The people who inhabit Ravenloft know that their land is plagued by supernatural evils. They might still cling to inaccurate superstitions about magic and monstrosities, but they harbor no illusions about the world around them. For example, the people of Barovia know that Strahd von Zarovich is a vampire—but there is precious little they can do about the undead sovereign who rules their land. (Note: WotC actually made this change to Barovia in Curse of Strahd. Good on 'em.)
Ravenloft with a Twist. Several bits of "lore" that I find silly don't make the cut. For example, the people of Darkon do not suffer from magical amnesia. In particular, the darklords’ backstories will be significantly different and, in the cases of the more convoluted origin stories, vastly simplified. It is unlikely that my version of Urik von Kharkov is a panther who was transformed into a man who later also became a vampire. Also, I feel absolutely free to add many factions, religions, secret societies, and nonplayer characters borrowed from the Ravenloft fan community and of my own devise. (Note: It will be interesting to see if there is one of those "the setting is yours to modify!" disclaimers in the book.)