Can I ask fans of Nentir Vale what features and themes really stood out to them back when it was a thing for 4e?
Well, my favorite thing about it was the unobtrusive way it was presented. Like a From Software game, there was a lot of rich and detailed lore about the setting, but it was all implied rather than directly stated, so players and DMs could engage with it as much or as little as they wanted. And engaging with the lore was less like reading a history book and more like piecing it together from all the little tidbits scattered throughout the books.
As for the “the world is trying to kill you” bit, I feel like that’s a Mearls embellishment. It’s true that the world was dangerous outside the scattered bastions of civilization, but the world wasn’t actively hostile towards humanoids, so much as wild and uncaring. Less post-apocalyptic wasteland, more Wild West frontier. I got a similar vibe from keep on the borderlands.
The Dawn War was one of the most interesting parts of the lore, of course. And the War of Winter, depending on whether you interpreted that as part of the Dawn War or its own separate event. It was cool having a setting whose present is so directly shaped by this massive titanomachy-like conflict between gods and primordials. Kind of odd that Mearls has decided that
all of the surviving pantheon were former mortals. That was explicit the case for the Raven Queen, and probably also Vecna, which was cool and made them stand out. But it seems like a very strange choice for others like Corellon or Pelor or Asmodeus. It also directly contradicts some of the established lore. Which isn’t a huge problem, it just, again, seems like a strange choice to me.
Speaking of the pantheon, I like how small it is. Most D&D settings have too many gods to keep track of, makes it hard for me to care much about any of them. Nentir Vale has a nicely sized one, enough to feel multifaceted, but not so many as to be overwhelming. And a lot of them have really cool combinations of domains in their portfolios. Of course, the Raven Queen is my favorite with Death, Fate, and Winter. Pelor is a really cool parallel with Life, Time, and Summer. Melora was an awesome combination of earth mother goddess and tempestuous sea goddess. Just a really rad pantheon overall.
Some of the non-deity-related history was really cool too. One of my favorite bits was the lore surrounding Bael Turath, the origin of Tieflings, and their conflict with the Dragonborn empire of Arkhosia.