Well, my current 'point of light' D&D setting is a small mountain valley kingdom, with human areas, a halfling shire, an elven forest, and dwarven hills. Humans are dominant, and the races keep largely to themselves, but all serve the same human king who once united them to overthrow the tyrannical rule of an evil sorcerer.
I'm doing that to a small degree in my upcoming campaign, but what lead me more to the melting pot is... do the dragonborn, tieflings, gnomes, (half-) orcs also get their own realms?
I guess that's my issue. I realize its just a game, but to some degree, I don't see how it's "fair" that dwarves and elves get their homes, but other standard demihuman races don't.
Maybe it's just that the other races don't have as well defined/stereotyped homelands? Is that an issue the "purists" have overcome?