AI changes its civics too often. So if AI is not spiritual it goes in anarchy and often ends in revolutions.
The second issue here is that they often take bad civics. In my last game three behemoth ai's took anarchy and chiefdom while having 25+ cities. End result - loss of population, science and revolutions.
This makes game too easy. You just need to stay in the middle of the list. Eventually your rivals will go into revolutions and you just grab anything worthwhile - cities, techs, resources.
The second issue here is that they often take bad civics. In my last game three behemoth ai's took anarchy and chiefdom while having 25+ cities. End result - loss of population, science and revolutions.
This makes game too easy. You just need to stay in the middle of the list. Eventually your rivals will go into revolutions and you just grab anything worthwhile - cities, techs, resources.