What's missing by Paizo

Although I've long since kinda stopped paying attention, I still pop in every so often and see what Paizo is doing with their setting development (they lost me a long time ago with rules development; they kind of took what was wrong with 3.x and made it worse).  They've started doing repeats; there are new(ish) books out for Osirion and Cheliax, for instance, even though I also have older books dedicated to those two areas of the setting.  That said, there are a few areas that really could use some more development.  All of these areas have been mentioned in, at least, the campaign setting book, Distant Worlds, or some other source, but none of them have sufficient development that they're ready to use in any meaningful sense, at least not without a lot of homebrew to get it ready (hence the use of that tag.)

So, what would I specifically want to see, and where would I decide to focus?

• Realm of the Mammoth Lords.  No relationship to my own long-running (although little has been done with it) setting tag MAMMOTH LORDS which actually more closely resembles the Savage Worlds setting Totems of the Dead, this is a polity or region with lots of prehistoric La Brean and similar megafauna, including warm valleys in the mountains inhabited by dinosaurs.  This, naturally, is sufficient for adventure in and of itself, but there's more: the region is surrounded by enemies.  To the north is the path over the crown of the world to Tian Shan.  To the west is the hostile Witch-Queen Realm of Irrisen.  To the south is the Hold of Belkzen, who's orcs often raid their southern reaches to capture their own megafauna for war platforms, and to the east is the Worldwound—once a kingdom that culturally, if not politically, was closely tied to the clansmen of the Mammoth Lords, but which is now a beachhead for a demonic apocalypse.  It also borders a small part of northern Varisia, and is very close to Ustalav, and the ties of Kellid blood cry out from all of those areas, as well as Numeria.  The Realm of the Mammoth Lords is kind of the last redoubt of Kellid culture.
• Akiton, the Red Planet, and the Pathfinder equivalent to Barsoom.  This is actually very sparsely described, but there seems like a lot of opportunity here; sword & planet romance all through the surface, but with strange Lovecraftian horrors buried in the ice at the poles, and other unique and unusual settings for adventure that are very different from that found on the "Hyborian model" design of Golarion.
• Nex.  Normally I'm not a huge fan of over-the-top high magic areas, but I'm a little surprised that this hasn't been further developed, given that it's the place in Golarion for high magic wahoo.  Geb too, I suppose.  Maybe the two of them can't be done separately, which means that the Paizo folks aren't quite sure what to do with it.
• Varisia.  What, you say?  There's tons of material for Varisia!  Well, yes and no.  There are sourcebooks for several of the cities in Varisia, including Magnimar, Korvasa, and the Pathfinder Burning Man analog, Kaer Maga.  There are several adventure paths set mostly in coastal, semi-urban Varisia.  But most of the rest of this vast area remains a big cypher.  I'd love to see something in the Varisian hinterlands above the Storval Rise; a kind of Pathfinder Old West almost, with Shoanti barbarians standing in for Indians and Huns or Mongols as the case may be.  Of course, Paizo would screw this up with the "Avatar Myth" which is just an expression of anti-white racism.  And I'd love to pretend like I never heard anything at all about Kaer Maga.  Blegh.
• Eox.  I've been fascinated by the concept of Eox, which —in many ways—reminded me strongly of the Atropus section from Elder Evils.  The two could be easily combined.  Not sure why the concept of an entire world of undead is so interesting to me, but it is.  I wonder; maybe this could also be combined with Thanatos, as described in Fiendish Codex I?  Sure, why not?
• Arcadia.  Sure, I can adopt my own MAMMOTH LORDS or Totems of the Dead to some degree to give me material that works as Arcadia, but why hasn't Paizo given us more than a single chapter on a single city?

A lot of what I'm interested in is extraterrestrial—either in the planes or the planets, which are virtually indistinguishable from each other, both being exotic and often hostile environments for adventure of similar esoteric provenance.  I've actually just about finished re-reading for the first time Distant Worlds and I'm finding that my old REALMS TRAVELER setting idea is one that I'm missing right now.  I might have to put together a hex map of the Realms as a next step.