And not so much. Aside from northwestern Mallorea, very little of the other continent is Angarak. The Karandans, the Melcenes and the Dalasians are related to the Ulgos and the servile underclass of Cthol Murgos, and they are a seperate one of the original races, intended for Aldur, but who ended up seeking various alternatives to following a god. For all intents and purposes they run the Empire anyway, dominating the administrative & commercial classes (and in a David Eddings book, that means they are the only merchants and bureaucrats, because a race is only allowed 2 or 3 professions, and one combat style, with at most, variations for infantry and cavalry).
Divine ordinance. In PoP, when some Alorns are speculating about the possibility of an offensive against the various other peoples to increase their power as the leaders of the anti-Angarak resistance, Belgarath fumes that the boundaries of the nations were established by the gods themselves. This is not even an exaggeration. The conquests of the godless race (who presumably lacked an advocate at the divine summit where the borders were established) by the Angaraks and of the Marags by the Tolnedrans would appear to be the only cases of a border changing in the last 3,000 years. Even Sendaria's coming into being was simply making the de facto stat of affairs de jure, as the land seemed to a kind of neutral territory between Aloria & Arendia. And of course, since their neighboring peoples were not compatible with any terrain aside from flat plains or heavily wooded forests, it never occurred to them to expand their rule over a considerable expanse of highly-arable territory!

The strong implication is that reproductive issues are governed by the Prophecies. It wasn't up to them. Although according to Polgara, the Alorns breed like rabbits, and when the Rivan heirs were concealed in Alorn countries, they tended to have lots of kids, so who knows where they were all going....

For me, the problematic issues of the map are actually climate and geography. Assuming the equator runs through Nyissa (it being a freaking jungle after all, you have the equatorial desert at the same latitudes in Cthol Murgos, which, if I am not mistaken, is just not something that occurs. The deserts are in two bands north of the equator (Sahara, American, Gobi, etc) and south of it at a similar latitude (Kalahari). Yet the Vale of Aldur's surrounding reaches are fairly north-temperate, despite being only slightly north of Nyissa. Assuming Tol Nedra as a sort of Mediterranean climate and Nyissa is more like an Everglades-type environment, that would put the equator somewhere through the Cthan Military District & the Great Desert of Araga and slashing across the eastern continent to just south of the Melcene Islands. So there is STILL an inexplicable equatorial desert. If we put Araga at about the same latitude as the Sahara in our world, that puts the island of transplanted Arends in an equatorial climate, which was NOT the experience of Garion's party as they traveled through that region. The equator as to be either near Perivor or the Turim islands, or if farther north, the Melcene Islands, particularly the largest one with the eponymous city. As I recall from reading those books more than a decade ago (crap, closer to two! ), at no time did the group in any of those places seem to experiencing a tropical or equatorial climate. Even leaving my suppositions aside, Perivor, with its European-Northern American climate, is SOUTH of "the Jungles of Gandahar" which, by its infrequent allusions in the text, is something like India or Indochina/Malaysia (elephants and hot & spicy food). I really think Eddings developed his maps with no real relationships to each other, which makes his attitude of asserted realism particularly obnoxious. Given the details he goes into about the real world basis for all his cultures and ethnic groups, there is a lot that simply does not make sense.

For me it's kind of ironic, since the sense of the world building and ethnicities and whatnot are what got me interested in history and social studies (along with the much better done, if less vivid to a teenage mind, WoT). One of my favorite ways to occupy my brain in boring classes was to draw imaginary continents on the back pages of my notebook, pressing hard with the geographical features, so I could then trace the imprints on the pages below, so I'd have several identical geographical maps, and then I'd fill in the varying political changes, inventing the rise and fall of states and empires, largely inspired by the histories of the Alorn kingdoms, or the breakup of Hawkwing's Empire. It's kind of disappointing to look back at the inepitude that inspired me, especially given the efforts Terry Pratchett took making a Discworld map that fit every mention he had made in a story AND the rules of geography and climate (actually consulting an expert who told him things like "you can't put a desert there, haven't you heard of rain shadow?" ).

I know lots of people would say "its the characters and plot development that matter, not the world-building" but this IS David Eddings, so it isn't like he can fall back on that, either...

Yeah, you don't have to say it. I can hear the response already: "Be nice, old boy."