Just two points on minor factions:
A. Minor factions are too passive.
While i agree that minor factions should not found cities (because those cities might then be easy conquest for major players) i think that they should be more active. They could really expand their city at least with some buildings, they could build troops and go conquering (and expanding this way) or simply waylay some caravans. They should however under no circumstances simply sit there.
B. Minor faction cities and green land.
As we know making land green or black is a result of the channeling ability of the souvereign. The minor factions dont have a channeler. Therefore their land should not get green color. If they really expand as proposed in A it would, however, be nice if their land would get arctic, desert, plains or swamp depending on their native environment.
C. Captured minor faction cities can not grow!
At the moment Minor faction cities can not grow beyond size 1 when captured. As a player i think that is limiting but i can deal with it by simply razing all minor faction cities i capture. However at the moment the AI trys to really build upon captured minor-nation cities. As you can see from the screenshot below, and the number of huts, the AI is really really sad that its captured city does not grow.
I propose to either add some option to transform the minor faction city to a real city (which would fit to idea A), or - as you remember Brad promised that each Minor faction would provide a unique resource - to simply remove the city upon capture and replace it by a resource village that produces said resource.
