I totally agree with Grigor, which said it better than I would ever have.
Also, to add about one point that I often read as a suggestion: I’m really not sure that migration should allow to change of climate (e.g. when migrating, passing from a Western European map to a Mesopotamian map). This would allow for far too much randomness, totally opposed to what I remember having read about the migrations happening by very little steps each time, with the passing generations, something I imagine would be more 30 km than 300.
Related to this, I’m not sure if we have actual data on the distance between neolithic sites, but I think 30 km between them would be far more reasonable than 300. 30 km is the distance walked for a day until the Modern Era, by merchants for example, either by boat, by feet or with a merchants wain – hence the common distance of 25 to 30 km between trade towns from Antiquity to Modern Era, either along rivers or along the inland trade routes.
My opinion is that whenever different climates will be allowed in game (e.g. with Middle Eastern DLC), we should be offered the choice between a random climate, or choose between the different possibilities offered by DLCs – and stick to it, with still would allow for varied resources in metals, stones, etc.
It’s only with the Iron Age that some Empires really stretched on very different climate zones, the most famous of them being the Roman Empire. Before that, Near Eastern Empires (Egypt, Mesopotamia, Achemenids, even Alexander’s Empire) stretched on quite similar climate zones, so probably the random map would fit really well until the Iron Age is reached by the (hopefully) fore-coming DLCs.
(Before there’s any negative comment: I’m not speaking here of world map, as we know since Neolithic there were long-distance exchanges, but of migrations).
Sadly, there’s no mean to ping the Archaeologists group, but maybe @joeroe could say if he has any idea on those things, as I remember having read him in the non-specialists threads?