There have been exceptions throughout the years, of course. Skyrealms of Jorune (mentioned in a previous post) went out of its way to shake off the European-ish expectations of its audience by creating an entirely alien world out of whole cloth. Some settings are deliberately modeled on Asian or African cultures (the excellent game Bushido comes to mind), but are usually set historically (even if it's a "fantasy history"), rather than a brand-new locale that merely resembles an Asian culture (TSR's Oriental Adventures being an exception; it's pseudo-Asian Kara-Tur was indeed analogous to the various pseudo-European settings out there).
Especially given the fact that I want to do a more folkloric treatment of setting, I find a pseudo-European approach to be perfectly in line with my needs. However, as a student of history, I find that many settings are missing what I would consider to be unique and necessary elements that made the Middle Ages what they were. These are Rome, Christianity, and the Threat From Outside.
A central theme of the Middle Ages was the attempt to recover the glory of the Roman Empire. It has been said that Medieval Europe suffered from a collective inferiority complex because they were unable to match the achievements of the Romans in architecture, military prowess, political achievement, and art. Some fantasy settings have expectations of lost civilizations, but they are often too remote from the "present" to have a cultural impact (in fairness, this is often deliberate, to allow for a sufficient sense of mystery when exploring the ruins of such civilizations). But in Medieval Europe, Rome was imminent. From Scotland to the ends of the Mediterranean, examples of Roman buildings, roads, aqueducts, etc. abounded. Classical literature was well-known to most people who were at all educated (one reason the neo-Classical nature of the Renaissance was able to express itself so thoroughly was that it wasn't unknown to the culture-at-large). The largest cities in the world were founded and in large part built by the Romans. Even Charlemagne's coronation was an attempt to re-establish the Roman Empire on a political level.
Part of the problem, of course, is that the very ancestors of the Europeans were the ones who had caused the downfall of the Roman Empire in the first place, and suddenly found themselves squatting in the middle of an Imperial infrastructure they had no idea how to maintain. The Franks, the Anglo-Saxons, the Goths, Vandals, etc. were all, to a large degree, the founders of Medieval Europe. The Gauls, Romans, Britons, etc. were pushed to the sidelines. So in addition to their collective inferiority complex, the more educated amongst the people had a nagging sense of guilt about having caused it all in the first place.
The second defining characteristic of the Middle Ages was Christianity. In the context of a fantasy RPG setting, it is not the specifics of Christian doctrine that are important (although, if one were inclined, a very credible "fantasy version" of a Catholic Church could certainly be designed), but rather its overall role vis-a-vis the culture and history of the region. Christianity presented a break with both the religion and culture of the pagan peoples. Starting in the Roman Empire, Christianity soon spread to the invading Germanic tribes, causing them to abandon their hereditary faith in favor of the new one. As each tribe had originally practiced a variation on Germanic (or Slavic) religion unique to their particular tribe, the effect was a certain homogenization. Where the Saxons had their Woden, and the Goths their Weodon, and the Vandals their Wotan, and so forth, now they all had "God". But the conversion, at least up until the time of the Protestant Reformation and even beyond, was never complete. Folk-customs and the practice of witchcraft maintained at least some of the pre-Christian beliefs in the living memory of the common folk, and created a dynamic tension between the "official" Christian Church and the impossible-to-kill memories of the ancient faiths. As late as the seventeenth century, Bishops were posting laws against various pagan practices.
It should be pointed out that monotheism is by no means required for such a thing. It is entirely possible that one, more organized, form of polytheism, could perform the same function. It's a subtle point, sometimes lost in the stories, but in REH's Conan novels, the faith of Mitra is said to have done much the same thing among the Hyborean kingdoms, but never completely. Ashura, Set, and other gods are still around, even if the faith of Mitra frowns on and opposes them.
Lastly, Europe viewed itself as a land beseiged. The designation of "Christendom" was a way to define the problem of us-vs.-them, where "them" was first the Muslims, and then the Vikings, and then turned to an internal problem which eventually erupted into the witch-hunts. Even though Europe itself was beset with internal struggles for power, wealth, and prestige, it was also the target of invasions from the Moors in Spain (penetrating as far as southeastern France until Charles Martel stopped them), Turks in the Balkans, and Vikings in northern Europe. The Popes responded against the Muslims with crusades and counter-attacks, and the Vikings eventually were victims of their own success, founding kingdoms in England and Ireland that were eventually absorbed wholesale by the locals (but not before re-energizing the same with their pagan beliefs, which were of course related to those practiced by those whose lands they were invading; the Anglo-Saxons' religion wasn't too far removed from that of the Vikings).
These are, of course, sweeping statements, and as such represent only the broadest themes that a European-themed campaign might entail. There were many other factors involved in European history; dynastic, cultural, economic, etc. But in terms of designing an RPG fantasy setting, three central themes I would include would be:
- Ancient civilization. A fallen civilization, with a higher level of culture and technology (or, at least, which is perceived to have had such) than the present, existed and the dream of re-attaining it fires the imagination of at least some.
- Cultural upheval. A religious or cultural schism with the past has caused a break with ancient traditions, and is striving to establish itself as a worthy replacement for those traditions. It need not necessarily be religious in nature; it could be the conversion from monarchy to democracy, for example.
- External existential threat. There exists a threat (or threats) to the entire society that is perceived, rightly or wrongly, to pose a mortal threat to civilization itself. This forces a certain level of unity which probably is at odds with the normal workings of politics.
In game terms, any of these themes presents a practical impetus for adventuring. Exploring the ruins of the vanished civilization, with an eye not only to plunder but to discovering and recovering some of their wondrous knowledge. Dealing with the practical implications of the conversion to the New Faith (or New Dynasty, or whatever the New is that is replacing the old). Fighting against the External Threat, joining a crusade or fighting a defensive action against an invasion.
I like the idea that these sorts of rationales for adventuring are implicit in the setting itself and stem from its own internal history and the implications that stem therefrom.