Protected the villages from barbarian raiders, which was of the utmost importance at that time. Tribal barbarians used to travel in small raid groups throughout the land, looking for small villages to pillage, violate the women and kill the men.
It's good for protecting herd animals from being hunted by wild animals, like wolves.
Cons:
It wasn't very inviting for commerce and cultural exchange with other villages. This prevented these protected villages from, for example, developing their technology in agriculture faster by exchanging knowledge with each other, what would enhance their capabilities and efficiency faster.
This type of village also doesn't allow its expansion.
Grid Villages:
Pros:
Not by chance, this pattern is used in big organized cities until nowadays. It is certainly one of the most effective ways to allocate buildings and houses from a productive angle. This way, you may concentrate governmental and public service buildings at the center of the village/town, and commerce buildings around it. This would give people fast and easy access to them, and make the village easier to rule.
It's also a good way to make the village suitable for further expansion.
From a security perspective, it's also effective since the most important buildings and houses would be concentrated at the center of the village.
Cons:
From a social perspective, it's not very good for newcomers, who would have to settle at the outskirts of the village, from both security and productive reasons.
It's very favorable for social-economic disparities, since those families living closer to the center, would become more favored by their condition by each generation, while the situation gets gradually harder for those living far, as you go further from the center.
Linear Villages:
Pros:
Also gave people easy access to work and public services.
It was also the easiest type os village to expand. One would simply have to be allowed to construct its house along that major road.
Cons:
It's not favorable for expanding.
It's very bad from a sanitary perspective. At that time, villages didn't have a sanitary canalization. What means that they all had to throw their waste on rivers or - in case of bigger villages - on the middle of the streets and let the rains wash it away. It's not hard to imagine how hideous the condition of a big thoroughfare like this would be. This, of course, invited the presence of countless disease-spreading insects and rodents, and with them, the diseases they spread.
Cluster Villages:
Pros:
This type of villages was formed by the eventual natural expansion of very well succeeded villages. This success was generally related to good geographical location (with an abundance of resources and good commercial position), and survivability to raids and wars. They would eventually grow into towns, cities, etc.
They were inviting for entire new villages to come and construct their own settlement. These villages would eventually become a must-visit waypoint for nomad commercial caravans, to the point they would start building their own trade routes themselves.
These would enable this cluster to become more and more powerful, and consequently its ruler. To the point he/she would proclaim himself/herself king or queen.
Cons:
They were also very suitable for sanitation problems.
Also favorable for social-economic disparities.
They invited a lot of competition for power (wars).
