This week's dev diary talks about Regions:
https://forum.paradoxplaza.com/forum/developer-diary/dev-diary-40-giant-kings-hand-crafted-regions.1731374/For starters, the free Ogre update will be getting some snazzy visual upgrades, including Arctic and Desolate mountains:
The update is also adding "sprawl": Houses and other structures will appear around your cities, and gradually spread over your core provinces as your kingdom grows. As someone who especially enjoys the immersion factor in games, this is something I definitely appreciate.
[The first two screenshots displays the difference between a Tier 1 vs. a Tier 4 city, while the third screenshot shows an empire with general sprawl.] 
(Note: The devs have mentioned the "intensity" of the sprawl will be dialed back before release.)
Getting into the
Giant Kings DLC, it will be adding Hand-crafted Regions to the game. These come in 3 types: Natural, Landmark, and Fated.
Natural Regions are apparently relatively commonplace (the devs have made a bunch of them), and can appear pretty much anywhere on a map. While they have no gameplay affect per se, it sounds like they will frequently be the locations for things such as ruins, ancient wonders, and the like.
In contrast, Landmark Regions are much rarer, with only 3 likely to be found on medium maps, and even the largest maps probably won't have more than a handful of them. Intended as both the game's equivalent of World Wonders, plus an "ultimate prize" for exploration, Landmark regions contain a single vast structure or natural phenomenon.
In contrast to ancient wonders or nodes, Landmarks cannot be claimed or annexed. Instead, they provide bonuses to the lands adjacent to them. As such, whoever discovers a Landmark will likely want to grab as much of the surrounding territory as possible. Also noteworthy is that they don't need to be cleared, so an empire that manages to discover a Landmark early on could have a major advantage.
Fated Regions offer unique quests & adventures to players, and are (as the devs put it) essentially small story realms. They're also complex and share connections with one another, and as such are not enabled by default. They're enabled via the new realm trait "Legends of Myrrida", which is also available in multiplayer.
Finally, we have the Crystal Dwelling. It's similar to the Umbral Dwelling in the
Eldritch Realms DLC, only it's inhabited by the new Lithorine units. While you cannot assign whispering stones to Crystal Dwellings like you would a Free City, you can improve your allegiance with them by taking on special quests or fulfilling other requests. Once your allegiance is high enough, you'll be granted access to their archive: a shop of unique spells, artifacts, hero items, etc.
So far, it appears I have every reason to be as excited for the new Regions as when I first read about them. The Landmark and Fated regions especially interest me, but new/upgraded visuals for the base game are definitely welcome as well. And who can say no to doing fetch quests for knowledge-seeking rocks?
