[For the sake of making sense, I'll be using the term "Mystara" to denote the 2e setting, whereas I'll use "Known World" to talk about it in its prior BX and BECMI incarnations. I hope that's clear enough.]
Mystara HerselfI honestly have no idea where to get started talking about Mystara; I'm ultimately horribly unqualified to discuss it at any length. I could go on about the Gazetteer series, the classic BX and BECMI adventures that drove the setting's early days and formation, but there are plenty of folks who could do a more complete, and better, job. But I've got to say something. And so, here goes.
Largely, Mystara reflects real world cultures at various points in history, mashed together. Sometimes, these are done by changing some names, but keeping the overall historical context consistent (like Thyatis), while others, a real-world culture seems to be fitted backwards upon a previously existing idea (like the Principalities of Glantri). It almost feels as if the intent was to be a real "kitchen sink" approach to setting design which left a lot of room for cultural relativism without recourse to a defined, objective "good." Given that the Known World was originally detailed in the BX rule set, it was made with the threefold alignment model in mind, which affords a lot st broader latitude to interpreting cultures and there mores. No nation is "Neutral Good," because there is no good, just neutral.
In 2e Mystara, the application of the 2e ninefold alignment system, to my mind, really screws with an initial strength of the setting: that while it represents echoes of real world cultures, it doesn't present any one of them as "right" or "the good guys," but the 2e-ification starts to apply these labels, which to me is a very bad thing. Sure, there might have been some obvious 'bad guys" before (the Black Eagle Barony), but now we have moral judgments applied about who is evil and who is good, where before these distinctions weren't nearly as clear, disarming both DMs and players alike of their own interpretations.
The "kitchen sink" approach of the Known World, I'll claim, works primarily because no single thing placed in that sink ends up being "the best" or "the good guys." As a result, stuff that really shouldn't fit together fits together exceptionally well with far less explaining away necessary. Each setting component has exactly as much right to be there as any other. That changes for the worse when TSR applies "good" and "evil" as objective, universal, metaphysical constants, making judgments about culture so common to the 2e era. Boring.
Here's the killer: that is my biggest gripe about Mystara. Other than that, I friggin' love it.
Hollow WorldWhen I was researching Spelljammer, I became aware of a term that Jeff Grubb likes to bandy about in what seem like self-aggrandizing ways: "Grubbian physics." I think far more interesting than Grubb's self-congratulatory number-jockeying is that which drove the Known World: the physics of Bruce Heard and Aaron Allston. These two gents jiggered and rejiggered the physics of the Known World to the point where not only are airships possible, but neither does a planet need its poles or interiors. These are the guys who made Hollow World possible.
Well, not so fast, Adam. The guy who really made the Hollow World possible was Edgar Rice Burroughs because he'd already done it back in 1922 when he called it Pellucidar. And yes, Pellucidar is the mark by which a "hollow earth" setting should be judged, not because Burroughs did it first, but because he did it so damn well!
The amazing thing is that, despite holding on to so many of the "genre D&D" tropes I typically despise, the Hollow World looks at these tropes in one that does justice to its Pelucidar roots. Here, we do not see the high fantasy of the Known World tooled down to match Pelucidar's prehistoricity; instead, we see the high fantasy tropes dialed backward in time to a point before the tropes developed quite so fully. Sure, we have dwarves, but they're not the same vault-dwellers we see in the world above but are surface-dwelling goatherds. Elves aren't the coolest, best thing on two legs. THERE AREN'T ANY GNOMES! Human cultures are interesting and rich. Magic is present but isn't pervasive. The whole thing jibes with my sense of what Appendix N literature is all about.
But wait, I cheated. This setting was produced for BECMI/RC D&D, not 2e. However (a) it was produced during the heyday of the 2e era and (b) later Mystara releases included Hollow World info and conversion notes, so it's only kind of cheating. All in all, I think that Hollow World is one of the strongest settings that TSR ever produced and stands on its own exceptionally well.
Red SteelOne of the stranger and more interesting adventures of the BX/BECMI era was the Expert-level (between 4-14th level) module called X9: The Savage Coast. I say strange because it really was full of some strange stuff. Turtle people, cat people, dog people; it's chock-full of shapeshifting spider sorcerers. Fun shit like that. I say interesting because it's a pretty darn large hexcrawl sandbox that does a good job of giving players a reason to explore and some goals along with plenty of guidelines for what could happen to them out there in the wilderness.
And so, given the opportunity to revisit this strange and interesting micro-setting, TSR did something weirder. Looking back at it now, there are some really strong late-80's, early-to-mid-90's trends that show up in the Red Steel treatment of the Savage Coast. First, consider the anthropomorphic animal races: the Tortles, the Rakasta and the Lupines. Do they come from the place as Teenage Mutant Ninja Turtles, the Cowboys of Moo Mesa and the rest of the anthropomorphic animal trend of the time? Also, the "Red Curse" of the setting - a magical power essence that super-charges magic, powers magic items and such - comes from the same place as the Kalevala's "sampo," manna from Heaven, imaginary superfuels of the future or, more contemporaneously with the influences of Red Steel, radioactive materials (which are often depicted at the time of having mutagenic properties that give rise to the aforementioned anthropomorphic beings). All PCs gain power from the Red Curse, but at the same time must constantly guard against its mutagenic properties. Hmm. Zeitgeist?
Red Steel is a fair-to-good setting. On its own, it would be okay. As a sub-setting within Mystara, it's not bad. As an inheritor to X9, I begin to come close to calling bullshit. I only come close because it might add a thing or two to the original (and giving Red Steel a vaguely South American vibe was an interesting choice), but it gives only half of the original mix of strange & interesting that I was attracted to in X9; it kept the strange but got rid of the interesting (hexcrawls had fallen out of favor by the time the 90's rolled around, as had sandboxes, in favor of heavy-handed railroad plots, a tradition which still drives mainstream gaming today).
Oh, and even TSR's reviewers in Dragon magazine said that the CD that came with Red Steel was a dumb idea.
There is at least one 2e-era setting I will not be talking about: Al-Qadim. I understand that many folks love it. I never read it myself, despite having several interests that line up with its flavor. Rather than half-ass some thoughts here, I'll leave you to yours. If someone wants to do a guest post analysis of Al-Qadim like I've done for these other settings, I'd be happy to host it.
When next I return to these settings, I'll look at what changes I'd put them through so I'd want to use them.