More larger cities and populations? Some domains do feel more populated. It's also very interesting that the idea of "Ludendorf University" is now canon, when I'm pretty sure it wasn't when I started inserting it into my games! In any event, I like that they don't really spell out population numbers for any of the locations; I find that stuff unnecessary and limiting.
More interconnection, particularly by sea Nope. Breaking the "Core" into islands in the Mists was always going to curtail that, but I don't think it would be hard to add in if you wanted to. Here's how I would do it: some seafarers and merchant caravans possess mist talismans that allow them to forge lucrative trade routes throughout the domains. Of course, these talismans are jealously guarded and work as objects around which you could craft some interesting adventures.
Down with fantasy racism YES. It is explicitly called out that the people of Ravenloft are used to strange visitors being pulled into their lands, so they don't raise a mob to murder every non-human they encounter.
The people know their land is horrible and haunted Mostly, yeah. This one was already implemented in Curse of Strahd, so it seems natural to extend it throughout most of the other domains.
Twists There are certainly a lot of twists, substitutions, and retcons in this version of Ravenloft. Urik von Kharkov is dead, long live Chakuna the huntress! I don't love all of the new takes on once-familiar domains, but they're mostly good. Some seem very cool, in fact.
Which brings me to what I want to write about. There have been many people covering the rules content in Van Richten's Guide, such as the new lineages, new subclasses, dark gifts, and other widgets, but I want to talk about the domains as a long-time fan of Ravenloft. How do they stack up, what alterations have been made, and how gameable does this iteration of the Domains of Dread feel?
Barovia is already a known quantity as its presentation in Van Richten's Guide is not substantially different from the domain as it is detailed in Curse of Strahd. Barovia is still Dracula's Transylvania with a D&D gloss. There are a few more bits of interconnection with elements that are new to this book (such as the priests of Osybus), as well as callbacks to aspects of the 2e and 3e versions of Barovia (such as Duke Gundar and Lyssa von Zarovich). The best bit in this section is a series of tables that can be used to determine Tatyana's latest incarnation and how he or she is connected to Strahd, either by trying to avoid his grasp or by hunting him. There's also a table for placing Tatyana in another domain if you want even more interconnection; Barovia doesn't feel quite so isolated anymore.
Bluetspur
2e's version of Bluetspur seemed like a domain suitable for exactly one adventure--destined to never really see the light of day once the module Thoughts of Darkness had been completed. The domain is still described as utterly alien and inhospitable, but at least it doesn't have rules for how you're going to be zapped by lightning every few feet until you find shelter as you're herded onto the narrative railroad.
Bluetspur is the prime example of "cosmic horror" in the book, substituting mind flayers for Lovecraft's otherworldly gribblies. This time, however, Bluetspur comes ready made with a reason why adventurers might find themselves in the domain: it now plays up the idea of "alien abduction," with the mind flayers stealing humanoids for use in their experiments to prolong the life of the dying God-Brain.
The surface of Bluetspur is still devoid of life; personally, I would have stolen a page from Lovecraft and placed a few remote, eldritch fishing villages here and there, full of the demented results of the mind flayers' experiments. Beneath the surface of the domain are the mind flayers' laboratory dungeons; the domain definitely amps up the sci-fi horror angle. There's also rival factions of mind flayers you could potentially pit against each other, with the adventurers caught in the middle. There's some rather nice writing in this section. In particular, I like this description of Mount Makab:
Calling Makab a mountain is a wild misnomer; it is a malignant deformation on a planetary scale, a spire with no apparent summit. Its contorted slopes stretch into the toxic heavens, and its form occupies the periphery of viewers’ attention no matter which direction they look.
Borca
Borca remains a domain enfolded in schemes and intrigue ala the historical Borgias. I like that Borca retains both rural villages and cities as part of its description; it feels like you can play through a variety of scenarios here, although the focus is definitely on the abuses of wealthy aristocrats.
Borca also preserves its two most infamous prisoners as its dual Darklords: the poisoner Ivana Boritsi and Ivan Dilisnya. The pair have been given a fresh coat of paint. Ivana's role as a seductive "black widow" has been diminished. I do miss her coterie of poisonous women, but I understand why the change was made--the sexual threat she formerly represented was not really in line with modern squeamishness. Ivan is very different; this version of him is a decrepit old man living in an extended childhood of murderous mechanical "toys."
Each of the sites detailed in Borca's write-up have strong hooks, even if their entries are short. Which is my preference, to be honest. They're terse, but they say something that gets me thinking about adventure possibilities. One interesting thing I noticed: the Scholomance, the mythical school of black magic mentioned in Bram Stoker's Dracula, is placed on the map of Borca! Was the Scholomance always a part of Ravenloft and I never noticed?