To contribute to the South Africa design, while I do agree with the concept of making Mandela's SA a very peaceful civ, I also believe in the philosophy of every Civ having at least ONE unique Military unit. And hear me out, because I think I have an idea, but I just don't know how to put it together...
South Africa has pretty heavily militarized police, that's for sure. And if you ask any
military historian armchair general racist on the internet, they'll tell you that South African police, especially their
Special Task Force, are extreme operators, and should easily be represented through a Unique Unit. Except instead of replacing Infantry or something, and being only useful in an aggressive late-game military, they could be a completely Unique unit, ala Switzerland's Combat Medic,
and only acquired when a Police Station is built. Weaker than standard late-game units, obviously, but receives a large combat bonus when in or adjacent to a friendly city, provides some sort of bonus when garrisoned in a city, like Mexico's Rurales (increases Happiness? reduces Happiness because lolpolice, but increases Production/Tourism?), and to keep with the SA diplomacy theme, and as South Africans did a lot of mercenary work during the Rhodesian Bush War (though the famed Rhodesian "British South Africa Police" actually had no affiliation with the nation of South Africa), perhaps grants additional influence when gifted to a city-state? Or maybe UberGeneral's idea of a CS-type-specific bonus from a unique Merchant could be woven into this unit, somehow? To get rid of that wall of text and summarize that into a complete design:
Special Task Force
Cost: null
Combat Strength: 45
Prereq Tech: Electricity
Unique Unit only available to South Africa, and may only be acquired by building a Police Station. Receives a 20% Combat Bonus when stationed in or adjacent to a Friendly city. When garrisoned in a city, decreases local Happiness by 1, but increases Production by 5% for each level the unit has, to a maximum of 30%. Generates double Influence when gifted to a city-state.
So as an end result, you have a military UU to appease those like me and keep SA militarily relevant in-game, yet severely limiting the NUMBER of those units you can churn out, making you develop your cities and focus on Buildings, and therefore still keeping with Mandela's peaceful/diplomatic theme.