After the results of the player survey came out, which I answered, I thought the devs had learned what the general issues of chapter 3 were, and why many players found it a good, but lesser experience than 1 and 2. I really enjoyed Blood West overall but I don't understand how the developer seemingly was able to ignore it while the problem got worse?

The issue is the map itself.

In Chapter 1, there was essentially 1 character, and that's the totem. He sent you off to various "Points of Interest," to look for and bring back evil items. These POI are time & place-appropriate, each with its own strong theme (Canyon, Fort, Mines, Church, Burial Grounds, etc.) They not only are large spaces of exterior and interior environment with their own subset of "small pockets of interest" (I'm using your term), between each POI there are connective passageways that allow you to approach each themed POI from different directions. For example, I can climb the Tower and end up in the back of the Fort, or descend the Mines and end up in the Canyon. Terrific exploration.

Chapter 2 has none of these connective passageways, but there are still a lot of subterranean spaces to explore. The POI in chapter 2 are arguably even better, with themes tied to the Bog. There's more character than just the totem now, I learned more about the world of Blood West through interacting with these characters. They had various levels of interactivity, granted, but it was a good addition.

In Chapter 3, while the theme of Forrest is good, there's fewer interesting characters to give anecdotes on the world in general. The doctor is the most significant of the new character (out of 2), and he didn't have a lot to say or do. It's also a smaller map, with no connective passageways between the POI. Often, to walk between two POI which are next to each other on the map, I have to walk all the way around. The experience is hurt by this combination of scaling back of intersecting characters and POI being approachable only from one direction (and once done you just double back where nothing happens, or teleport out). I think the POI are still very ornate and interesting, but they feel... 2-dimensional?

Finally, DLC. The DLC map is by far the weakest of the 4 maps. The Points of Interest here are barebones versions from the other maps. The Fishing Village is the Town from Chapter 2, only smaller. Church Cemetery, Ruined Village, Farms, are all insultingly small, barely have anything to explore. The Other World is interesting, but again it's all one directional tunnels. New creatures do all fit the game, especially the birds that sit on trees, they can really surprise you on your first playthrough. The final boss is the best in Blood West, interesting, fun, an improvement over the decidedly low bar set by the others. Maria as the voodoo totem is sort of interesting, but her exposition is held back by the map size. The skeleton is basically another Jim Hooper, a cardboard cutout with nothing to say but act as the shop. We know going into it that we play as Twen's father, but there was not a single mention of Twen or anything associated with her except in the intro cinematic, and the outro cinematic...

So my question at the end of this is, what happened? Why has the core part Blood West, the map, the exploration, degraded so much since chapters 1 & 2, even 3? The turnaround on DLC is one year, like previous chapters, but the map is 3/10 at best? The place was so small I barely used the raven skulls to fast travel back to safezones - I just legged it. It feels like a critical developer or two left the project, and those back-filling them aren't up to the task, or don't care for Blood West nearly as much. Or, it's just really, really rushed.