Quote Originally Posted by LurkytheDwarf View Post
Incarnate, Shadowcaster, Rogue, Barbarian, Scout, Spelltheif, Paladin, Ranger, Ninja, Adept, Fighter, Marshal
Some of these work really well for S&S, though the Paladin is weird. So, let's talk genre tropes, and how these fit.

Weird Sketchy Magic: The Shadowcaster, Incarnate, and to a lesser extent Spellthief all work pretty well here. The Adept works less well, but what I do like about them is that they're not particularly coded as scholarly arcane casters. You could probably drop the Arcane/Divine split (which is one of the things that makes D&D feel so specifically D&D in setting), and play up the plethora of tiny gods side.

Types of Civilizations: It's really common in S&S for there to be 3 broad categories of civilization (though it's a trope that can get gross and racist fast if not handled with caution, especially if you're taking influence from 1930's and 1940's work uncritically). Still, the decadent and decaying heavily urbanized civilizations work, as do the clannish "barbarian" cultures, as do the more anarchic, undisciplined "savage" cultures. The martial classes can form a nice continuum across most of this, very roughly in a Rogue->Marshal->Fighter->Scout->Ranger->Barbarian distribution. The ninja and paladin are a bit weird.

Broadly Iron Age: S&S isn't usually particularly historically rooted, but inasmuch as it is it's usually more bronze age to iron age, extending a bit into pre-Roman classical. This ties into the magic a bit, as the mage/priest/administer archetype works really well with a fantasy version of ancient Mesopotamia in particular, and oh look, there's that Adept again, perfect for the role. It also helps that we don't have the Knight and a few other more thoroughly medieval classes around, though again, the Paladin is the odd one out.

Cults: Weird secluded cults are a whole thing, often tied to the aforementioned sketchy magic. While it would be really helpful to have the Warlock and Binder around, the Incarnate works so well as a cultist of some sort. This also might be a place where paladins can be incorporated, as some sort of cataphract order tied to a benign cult associated with a minor steppe horse god. Though the alignment requirement and S&S tropes are still not playing as nice as I'd like.

Obviously there's also the class-as-detached-mechanics approach which nullifies a lot of this, but if you're trying to derive setting from classes that seems like an incompatible decision.