Mkay, so here's my take on the subject:
The 6 villages are not part of one united nation, but 6 city-states like in ancient Greece. They're all basically their own countries. Also, the different types of Matoran don't all each live in one Koro, as there are not only a couple large demographics among them but some natives of other Koro may have migrated to others at some point in time. The total number of Matoran types would ideally be more than 6, as that makes adding in representatives for the secondary elements easier down the line. The size of each Koro might be just enough to form a small archipelago together, or it might be up to a continent.
Ta-Koro has a lot of volcanic activity, and its forests are comprised not of trees, but of great fungi that thrive where plants could not. Its economy is largely based around the business of lava farming (wherein workers extract metal from Mt. Mangai's lava flows) and smithing. The term "fire-spitter" is a term of endearment among Ta-Matoran.
Ko-Koro, high in the mountains, is largely a nation of scholars and thinkers. Its people possess a rather cold atmosphere to them, and mostly keep to themselves. Its economy centers around selling useful inventions, which is derived from the Ko-Matorans' high regard for ingenuity. In the past, it has warred with Ta-Koro, so tensions between the two Koro are high.
Le-Koro is a village nested in the treetops. Selling off work Rahi and plant products is the basis of its economy, but the Le-Matoran consider music and festival to be the truly important arts of life. Their relationship with nature is also given great importance, and the Le-Matoran would readily go to war if even a small part of the forest was jeopardized by any other Koro.
The desert village of Po-Koro is home to the greatest Matoran artisans and craftsmen. A well-made sculpture can go for thousands of widgets, and so the upper-class Po-Matoran have quite a lot of spending money. All Matoran love the sport of Kolhii, but none so much as the Po-Matoran, who also make great profit on selling seats for Kolhii games.
Buried under the ground lies Onu-Koro, where mining is the source of economic activity. The friendly Onu-Matoran consider mining one of the few "real jobs," but don't really say it that much to anyone else. They're the chief supplier of lightstones, which aren't that useful outside their own village except at night.
Ga-Koro is built on a partially sumberged landmass, and so its chief mode of transportation for its citizens is not Rahi-pulled vehicles, but boats. This prowess in anything boat-related has made the Koro the Matoran trading hub, where most everyone meets to hawk their junk at everyone else. They're also a spiritual center, being the site of many temples and religious monuments. Matoran seeking the favor of Mata Nui generally come here to revitalize their faith.
Just my thoughts on the matter. I know it's really specific, but I wanted something that was distinctly derived from G1 without having something that didn't feel like its own thing.