As a thought experiment, I've been looking at the revised tiers list and been thinking about what such a setting would look like using only one tier for all the available classes. Tier 4 (minus Dragon magazine and UA generic classes) inspired me the most, so I went with that.

Classes: Incarnate, Shadowcaster, Rogue, Barbarian, Scout, Spelltheif, Paladin, Ranger, Ninja, Adept, Fighter, Marshal

Half the iconic four are present (Fighter, Rogue) which points me in the direction of a setting more in the Sword and Sorcery genre like that of Lankhmar and Conan: episodic adventures, no world-threatening dangers, exotic locals, Arabian Nights, magical monsters and evil sorcerers.

A full third of the classes are either primitive or at least wilderness-based (Adept, Barbarian, Ranger, Scout). So the world should probably be very wild with vast tracks of untamed lands. Civilization tends to be very tightly concentrated, Points of Light–style city-states/kingdoms (something akin to that described in The Howling Emptiness of the World of Greyhawk by the Hill Cantons blog). Lone rangers tirelessly patrol the borders, warning towns of impending dangers, and tracking down missing caravans. Only rugged barbarian tribes dare dwell far out in the wilderness, aided by their wise women and witchdoctors (Adepts).

There's also a warfare theme in the classes as well (Marshal, Scout, Ninja). So war is common enough between the Points of Light that there are many former army commanders and scouts (very necessary to aid troops moving from one kingdom to another through the harsh wilds safely). I'm inclined to believe its the Points of Light at war and not monstrous humanoid hordes due to the presence of the Ninjas, which owes itself to an intense layer of intrigue, assassination, and espionage between sophisticated powers. Maybe the kingdoms aren't kingdoms but noble houses/clans/guilds seeking to protect their rice farms and poppy fields and steal those of their neighbors.

The Shadowcaster falls in with the theme of Points of Light and dark wilds, with the implication that the Plane of Shadow is encroaching upon the world. Perhaps Dark Creatures, Shadow Mastiffs, and the like hunt in the forests. On the surface, it would seem they are diametrically opposed to the Incarnum (the magic of souls/life). Maybe Shadowcasters get a bad rap while Incarnates are thought of more highly (when in reality a quarter of all of them are dedicated to evil) and there are probably more than a few Shadowcasters who use their powers for good.

While Spelltheif can steal from Adepts, Rangers, Shadowcasters, and Paladins, their own spell list implies, along with the Sword and Sorcery genre above, that there are at least some traditional magicians in the setting, but they would never become adventurers. They are all old and either cynically aloof or crazy, building weird dungeons for unknowable purposes, experimenting on people, and/or traveling the planes leaving their towers to be plundered by those foolhardy enough to try. Spellthieves will try, they've already figured out a little of the wizard's magic themselves, and always game to steal a little more.

I'm sorta at a loss for Paladins because at first, this doesn't seem like a world which has many gods, or where the gods are very present. The divine magic either comes from communing with nature (Rangers) or some sort of secret traditions passed down through generation (Adepts). I assume they would be the rarest class, as the setting outlined above doesn't necessarily feel like it tolerates traditional heroes very well—the barbarians too chaotic and the ninja-employing nobles too evil.

What are your thoughts on how to incorporate the Paladin? Do you have any ideas which expand on those outlined above? Or when you look at this list of classes does a completely different setting come to mind?