Civilization traditionally meant "Cities" and still does to even some Academics (which is why some speak of a distinction between Civilization and Cultural Entity/Group) and, of course, that is what Civilization the game has always emphasized. From as far back as I've played the game (Civ 2) the game has always revolved around the City as the basic and by far the most important feature of the game.
Having been dragged into a few Cultural Anthropology and Cultural Geography courses in college (by friends and my sister who insisted that my intellectual life would not be complete without them - and they were right) I've never been able to accept this premise and always thought it limited the game immensely and unnecessarily.
Specific to this discussion, there were some very wide-spread and well-populated Neolithic groups that, at least, built what I call 'proto-cities' - congregations of population numbering in the hundreds or around a thousand or two, but unable to grow larger because their food sources were too ephemeral: lots of hunting and gathering still, primitive agriculture that could go bust on them at the drop of an environmental/climatological hat and force the abandonment of the settlement completely. Playing with this concept - cities that may or may not survive the next 20 turns, food sources hat come and go at near-random - would be a very hard sell for most gamers.
On the other hand, there were also a great many Neolithic cities: Jericho, Motza, Nevali Cori and Asikh Hoyuk in Anatolia - every one of them established prior to 7000 BCE and holding 2000 - 6000 people, but also requiring very specific advantages to be established: water sources, food sources, defensive advantages - cities did not start at random or easily.
But, by the proposed date of 5000 BCE, here are 'city like' congregations everywhere: Nabta Playa in the Egyptian desert with 5000 people, settlements in the Dadiwan and Peilagang Cultures of China with large ceremonial buildings on prepared, elevated foundations, Seskla in northern Greece with 5000 or more inhabitants, Vinca Culture futher north in the Balkans with several settlements of 4000 or more people, Ugarit which had its own stone walled defenses by 6000 BCE.
And, long before 5000 BCE, many of these groups already had fired, decorated Pottery, domesticated Cattle and Sheep (including the technology to make, store and preserve cheese as a 'secondary product') and by 5000 BCE were already starting to smelt Copper and enter the Chalcolithic Era.
So, 5000 BCE is just Too Late, even though the majority of the human population was semi-nomadic still, too many of them in too many places were already settling down and concentrating population in groups larger than simple hunter-gathering would support.
I suggest that 9000 BCE is a better date, with a very long-scale turn (60 - 100 years?) for the period before about 4000 BCE. 9000 is about the first evidence of domesticated wheat, millet and/or rice in areas as distant as Mesopotamia, Anatolia, Egypt, India, and China and just before the first indications of potato cultivation (8000 BCE) in the Andes, and the domestication of sheep and pigs - with cattle following shortly afterwards (7000 BCE). Pottery, Weaving (plant fibres, no wool until after 4000 BCE), coastal sea travel to islands (Cyprus was settled with domestic pigs and sheep by 8000 BCE) so there is a lot going on this early.
- Far more than Humankind represents in their 'Neolithic Start', which is why I think it belongs in Civ VII, only better done with more of the real complexities, technologies, and varieties of 'survival strategies' being practiced.
The fact that no recognizable "Civilizations" are on the board yet can be an Advantage: this period would be an Establishment Period, in which you start either Cities, or Settlements, or domesticate enough animals to be prepared for a Pastoral Civ - which life-style is not possible for large groups until after about 4500 BCE when you have domesticated cattle and the first domesticated horses to haul your household goods across the plains on travois - wheels come about 1000 years later. All that you do from 9000 to about 4000 BE would be preparing the groundwork for choosing the Civ you are going to play, and taking on a set of characteristics (Uniques) of that Civ - some of which might be established regardless of the Civ by your preliminary actions. For example, there were several archeologically-identified 'cultures' in China pre-4000 BCE that were shore-based and sea-oriented, even if they couldn't venture too far from the shore yet - why not a China with a Naval Unique from 4000 BCE?