Figuring out a way to accurately represent "these were advanced and powerful civilizations that for most of their history did not have settled cities" within the game, is a huge task, but a hugely important one if we want this game to truly represent world history.
As mentioned, this conversation can and should wait until Leoreth starts dealing with the 'civ slots' issue. I'm mainly writing this to brainstorm, and so I don't forget some of the ideas that are popping into my head.
1) find a way to represent the 'inner tribes'/'outer tribes' division in most nomadic confederations. This was true of the Scythians, the Huns, the Turks, the Mongols, and most likely the other steppe tribes that I'm not as familiar with, as well as the Iroquois and other Native American tribes. Basically: the single tribe/clan/family in power would surround themselves with several close allied groups, which would in turn be surrounded (often geographically) with other tribes and factions, more distantly allied, typically controlled by the inner group (without receiving the same benefits as received by the inner tribe). This might be represented via civics. More ambitiously, it might be represented by giving nomadic civs limited control over their full empire -- you can identify targets and declare war, but the 'outer tribe' armies might act independently of your control (though you benefit from their victories).
2) find a way to represent nomadic 'tent cities' -- not just their mobility, but the fact that they benefited mostly from flat grasslands since that's where their horses and other livestock could thrive. Disincentive nomadic cities from settling near hills or forests that ordinarily have better production. One possibility: nomadic cities are
only able to work grassland or plains tiles. Alternately, nomadic cities might be limited to only working tiles with pasture-resources (horses, cows, sheep, etc.) but receive must better bonuses from those resources. Find a way to tie total units produced to number of horses/animal resources? (With the bigger map, we should consider adding a
lot of horses and similar resources to the steppes in that case). Also, make it possible for 'tent cities' to become real settlements. Karakorum becoming an actual city during the Mongol conquests (specifically as a result of loot and captives being brought back to show off) is a good example, though there have been many others before and after them.
3) provide options for the settled civilizations to either a) bribe the 'barbarians' into not attacking them, b) vassalize one steppe tribe so they attack other unfriendly tribes, c) become vassalized without losing their autonomy or separate administration. China for most of its history had a very sophisticated system of diplomacy to keep the steppe peoples at each others' throats and away from the northern Chinese plain. The Byzantines had a similar diplomatic policy, albeit even more complicated. The Byzantines were also known for relocating different steppe tribes away from the frontier they would normally threaten, and deploy them to an entirely different frontier as mercenaries/warm bodies to fight barbarians on a different border.
4) the nomadic people of the steppes were known for two things -- regular invasions into the settled regions south of the steppes, and heavy sustained involvement in the cross-continent trade that later became known as the Silk Road. Figure out a way to represent the trade aspect of nomadic life, especially the middleman role of the Tarim Basin (west of China) and Transoxiana (north of Iran). No idea how to implement this, though I suspect it should be closely tied to the diplomacy mechanic above.
5) find a way to demonstrate how nomadic people were able to migrate, conquer, and settle new regions that became their new heartland/core. The Turks invading Asia Minor are probably the best example of this -- the Turkic people originated out of the same region as the Mongols, but had little difficulty in moving their homeland across most of Eurasia when they moved into the Anatolian highlands. I am no programmer, so this might be impossible to implement, but I wonder if it'd be possible to design a 'dynamic core' system, where civs can change their own settler maps over time due to population and culture (e.g. Rome starts with a very small core limited to Rome itself, expands to the rest of Italy, then gradually adds a few more major cities around the Mediterranean as they are integrated into the Roman system). If this mechanic were generally permitted for most civs, then it'd be a matter of changing the modifiers for nomadic civs, so they'd find it easier to make new 'core tiles' (and easier to lose old core tiles) as the population moves into a new region.
6) find a way to represent just how absolutely
freakish the Mongol conquests were -- both in terms of administration, and in terms of how quickly new areas were conquered. Normal steppe tribes should have certain advantages (especially in stronger cavalry), balanced by unique disadvantages (much less population, poor organization and administration, etc.). The Mongols should receive the full benefits of nomadic tribes
and settled civs -- strong cavalry, huge population, unparalleled administration, etc. One possibility for showcasing how
fast they moved, would be having their unique 'ger' building give a mobility promotion to all units, with +1 movement and 'commando' abilities over poor terrain. Basically, find a way to represent the Mongol army as being entirely comprised of cavalry, even their siege engineers, enabling them to move across the entire Eurasian steppes in a few turns without having to wait for their slow siege weapons.
That's all for now.
