Alright, good to know.
I'm currently adding a two-civic category called "Nomad or Settled". Both civic options have no upkeep. Settled offers no bonuses or maluses, and becomes available at Sed Lifestyle. Nomad gives the following:
Positives:
+ Mil Production
+ Free Units
- Mil Maintenance
- City Maintenance
+ Great Gen
+ extra gold from Pillaging, city capture
+ mil exp
+ hammers from nomadic camp, camp, jungle camp
+ gold from basic resource gatherers
- disease
- crime
Special Units (mainly horse archers)
Required for certain wonders (uighur, Mongol, Tengri Shrine)
Negatives:
Massive Farm Build time and upgrade time (complete lack of agriculture)
Massive adv. Resource gatherer build time and upgrade time (wineries, orchards, plantations, pastures)
Higher than road massive build time (very long time)
Much less buildings
Increased rebellion
Cannot SETTLE more than 6 cities, EVER (perhaps scale-able by map size)
Large relations hit from settled civs
Less Buildable Units
Everyone starts as nomad, and most civs switch to Settled upon getting Sed Lifestyle.
Now, when you're as a nomad, you're completely lacking in agriculture, and your populations stay rather small. But, you are rather effective in the improvements that you can build. What's more, you can field a much larger army than settled civs.
Why can't you build more than 6 cities? Because, historically, nomadic tribes never really got big by themselves. They mostly spread by invading neighbors. Settled neighbors, mostly. So you can have a massive empire as a horde, but it requires conquering your neighbors as opposed to city spamming.
Some units would be exclusive to Hordes, mostly horse archers and their cultural deviations. Some buildings as well would be exclusive to nomads, such as the Ger.
Eventually, the hordes will wane in power in the dawning of castles and the renaissance, as they will be limited in population size (and therefore technology) and military capability (they cannot build most military beyond early gunpowder). By the industrial age, they are screwed.
Here's what I'm trying to figure out: I'm trying to figure out how to make the civs keep nomad after Sed lifestyle, but still switch to settled later. Perhaps I can make a propensity for civs to keep nomad, but after a civ enters the industrial era, they feel much more inclined to settle down.
I'm also trying to figure out how this works with the Agriculture Category. It makes little sense for a civ to have virtually no ability to build farms, yet have "agricultural guilds" as an active civic.
Is changing the relationship modifier enough to make hordes and settled consistently go to war with each other? Or is there a way to mod in some increased aggressiveness for nomads?