But I basically tried to preserve the mold of the scenario.
I developed seven designations for civilizations:
"English" Civilizations: the Celts and Goths, with access to some medieval traits associated with the English. (Goths are the closest the scenario has to Angles/Saxons/Anglo-Saxons, Celts are already indigenous in the scenario.)
"Iberian" Civilizations: the Celts and Carthaginians.
"African" (and to a lesser extent, "Asian") Civilizations: the Carthaginians, Egyptians, and Persians.
"Barbarian" Civilizations: the Celts, Goths, and Scythians.
"Civilized" Civilizations: the Romans, Carthaginians, Macedonians, Persians, and Egyptians.
"Player" Civilizations: the original four player civilizations, Romans Carthaginians Macedonians Persians. AKA, the Player-four. AKA, the war-four. Terms to that extent.
And "Non-player" Civilizations: the original four NPCivilizations, Egyptians Celts Goths Scythians. AKA, the peaceful four. Terms to that extent. (Of course one of the first changes I made was making each playable, but the term remains useful.)
Each designation serves a purpose.
There are English units, there are African units, there are Barbarian units, there are Civilized units, and there are certain traits universal to the player-four compared to the NPC-four. (I wanted to maintain balance by making those that start at war not be at a disadvantage due to the war, thus, those that start at war have an edge over those that start at peace. Because a war you can't control obviously can have consequences compared to a war you can.)
I also made each civilization have specialties, based around my perception of them.
Carthage emphasizes mercenaries, thus, has a wide variety of units at their disposal...when the appropriate resources are attained. (Units which drew some inspiration from the game Nemesis of the Roman Empire.) Carthage also emphasizes early naval dominance, having a unique sea unit as well as their starting galleys buffed to be elite.
Rome emphasizes terraforming, colonization, and lategame militaristic dominance, thus, has a wide variety of powerful units at their disposal which double as a makeshift work force when needed. (Their units draw from Age of Empires, Age of Empires II, plus ALL eras of the Roman empire present in Civ 3 Conquests: Rise, Fall, and via the Byzantines, Medieval.)
Macedon emphasizes the phalanx formation, as well as trusting in the "wall of wood": naval dominance, thus, two unique naval units, one of which is the undisputed best of all naval units in the scenario.
Persia emphasizes a variety of units, as well as masses of them. The Persians were basically renowned for bringing millions of troops--while most assuredly exaggeration where their actual numbers were in the hundreds of thousands (still impressive against a fighting force which would be hundreds or maybe thousands but certainly not hundreds of thousands), they have that heavy emphasis on not only a LOT of units but also a large variety of units, units that span the entirety of their empire for where they come from.
Scythia emphasizes horsemanship, thus, multiple units based around it. They also were given, via inspiration from age of empires II, the unique Scythian Shaman unit, emphasizing elements of mysticality which I associate with them for out-of-game reasoning. (Or rather, different-game reasoning.)
Goths I associated with a mass horde of units good on the attack but lacking in defense, but also with being essentially the closest the scenario has to forerunners of the vikings--thus, masters of the sea. They also represent the forerunners of the teutonic knights to me, so they have that available to them, too.
Celts, via their Gallic Swordsman being identical to a Swordsman just fast, I associated with "mobile infantry": fast-moving versions of normal units.
And Egypt, via their lore of being a civilization on the decline, I associated with "player self-imposed challenge", which would be a difficult civilization to master, but fully possible, via two opposite playstyles equally viable for a player but which require full commitment (something the AI lacks as it goes for half of one, half the other, and that never works out): complete warmongry (of savescumming and fighting the nearby empires for dominance of Africa and Asia Minor), or complete pacifist (via having no unique units that can be used offensively and aggressively).
I also made basic unit classifications.
"Spear" units, loosely defined as "Defensive" units (even though not all defensive units are spear units and not all spear units are defensive)
"Sword" units, loosely defined as "Offensive" units (even though not all offensive units are sword units though every sword unit does happen to be an offensive unit if you count 'offense value higher than defense' as the deciding factor)
"Bow" units, loosely defined as "Support" units
"Mounted" units, loosely defined as "Speed" units (even though not all speed units are mounted, though all mounted units are in fact speed units)
"Explore" units (loosely defined as "any non-worker unit that treats all terrain as road", even if they don't have the explore box ticked)
"Terraforming" units (even though all but three--one of them in the original game, the base worker--don't work due to stupid programming limitations)
"Hidden Nationality" units
"Naval Power" units
"Naval Artillery" units (even though thanks to a programming limitation this doesn't work; the AI sees naval bombardment and power as synonymous)
"Naval Transport" units
"Naval Explore" units
"Naval Hidden Nationality" units
And "Building/Government-exclusive" units.
Obviously, there's overlap in quite a few unit categories, but. That's the general gist of how I divided the units.
Each government was thus reimagined as having one trait which made them be unique, but vastly inferior to the three "choice governments". (Tribal Council due to free units, Imperialism due to free units in a different way via a coding oversight present even in the original game!, Oligarchy as starting government until you can switch to Imperialism safely.)
To the map, I made eleven changes.
I added rivers, rivers everywhere. Mostly just 'cuz. This change didn't really serve much of a purpose other than satisfying my personal preference.
I added roads, roads everywhere--especially near Rome, where every single tile except those occupied by a Barbarian tribe has a road, leading into the Celts, Goths, and Macedonians; everything from the silver a little southwest of Masillia to the silks in the middle of nowhere, roads.
I added forts to that same area for Rome.
I added random barricades in locations sporadically throughout the map, representing some of my favorite settlement locations. (Basically a way of saying, "I'd put a city at or near this spot".)
I made some modifications to a couple of spaces, deleting forests in favor of coast in order to allow for naval shortcuts if founding a city in the right spot. (Mostly for Ireland and England, but there's also that spot which in the Medieval scenario is where I believe it's Denmark would be; I made it possible to bridge the ocean and that sea which in the vanilla game is landlocked.)
I added barbarian goody huts sporadically throughout the map--and placed heavy emphasis on some around the player four civilizations, once more to emphasize: these four civilizations get an advantage compared to the four original NPCs.
I added Barbarians sporadically throughout the map, mostly Russia, and reinforced heavily those that are around Rome. (Mostly for grinding purposes, of causing the conscript units to become regulars and even veterans.)
I added a few bonus resources here and there, especially to marshes (every marsh spot has some kind of resource on there because if I'm gonna have to deal with clearing the marshes out due to their disease I'm gonna get something out of it, dangit!), but did add a few resources. In Africa and Asia minor, there's a little more of what was already there, basically. Ivory, Silks, Spices. One spot in Africa has gold, silver, and gems added, but takes a long time to reach. (Similarly, the Oasis in Africa also has some bonuses, but is time-consuming to reach.)
Across the whole map, I added an eighth luxury of Wool, too.
I terraformed a fair number of spots, mostly adding irrigation to deserts and quite a number of plains with the occasional grassland irrigation thrown in for good measure: wherever there was a spot that would normally be impossible to reach, I added it. Speaking of which, every island got roads pre-added, many spots got pre-mined, and many more got pre-irrigated, due to the pain of transporting units there.
The four player civilizations were given outposts. Rome's are particularly noteworthy, as they allow first-turn contact with the three barbarian civilizations, and contain units pre-loaded onto them to defend them from attack. (To compensate for this, Carthage was given more starting Numidian Mercenaries as well as starting with some War Elephants, particularly in Hispaniola. Which, I felt, was thematically appropriate--and as I learned, surprisingly devastating to go up against!)
Most extensive of all though was the adding of units.
Each NPC starts with an Army now.
To compensate for this, each original player-civilization was given three of their initial golden age unit with elite experience based in the same city as their army. (Three Legionary Is experienced elite, three Hoplites experienced elite, three Immortals experienced elite, three War Elephants experienced elite.)
I developed a naval unit, the naval blockade, which can't be build and is immobile, and had each of those four start with a fair number. Carthage blocks off the pillars of hercules plus has presence near their starting islands, Rome also has presence near those islands as well as blocking off the lower half of the passageway through the island of Crete to Africa (or whatever that land is), Persia has a naval blockade which was my attempt to simulate Xerxes' Pontoon Bridges, and named them such, though because I was lazy and couldn't pinpoint precisely where said bridge would be, they blanket basically that whole sea. And Macedon blocks off any non-Persian square in that same sea, plus some spots near Italy.
There's also a Celtic one blocking off the narrow point between England and mainland Europe, plus Barbarian ones throughout that same area.
I gave the Romans a unique unit, the civil defender, envisioned as a "mobile defender": high early-game defense, and respectable lategame defense, but with an extra movement point as to keep pace with Roman Citizens and defend them from attack (since what good is two movement if your only way of covering them is with cavalry units that specialize in offense and have virtually no defense?), and placed them on each spot with a citizen (plus a couple extra which I thought had citizens but didn't).
To compensate for this, Carthage and Macedon got one extra settler in their capital city; Persia got two. Each also got their preferred defensive unit for said settler; Carthage got a Numidian Mercenary, Macedon a Hoplite, and Persia two spearmen. I may have given them one additional defensive unit prior to that, too, considering you start the game regardless of civilization with a settler unit--and normally, lacking the extra defensive unit to cover said settler.
From there, it's just a matter of specifics for the modifications I made.
I feel I did successfully preserve the dynamic of the civilizations, too, for what it's worth. Carthage always starts out lacking manpower compared to Rome, but having more cities than Rome. Carthage can take Sicily if lucky, but once Rome launches her initial invasion, all of Carthage's islands can fall, depending on the roll of the die. Soon, Carthage gets access to War Elephants relatively early, and storms Rome, launching a counter-offensive with their gained manpower. But when Rome gains Legionary IIIs, the tides turn against Carthage. Carthage eventually loses the Iberian Peninsula, and probably their islands, too, but Rome always lacks the manpower necessary to launch an invasion of mainland Carthage, stalemating the two. Unless at any point, the player intervenes on behalf of one.
Persia starts out with a manpower advantage over Macedon, but Macedon starts with their forces concentrated densely into a tight area, and is able to launch an initial wave of attacks. Eventually, Macedon controls the sea. Usually, Macedonia can control some Persian cities, such as Icosium (or was it Iconium?) and Ancyra, but after the Persians take the long way around, they start to lose ground. Ultimately, they juggle back and forth and it takes player intervention to break the stalemate.
Egypt is at a disadvantage, but can expand aggressively to the point of being the second-largest civilization in number of cities. As an AI, she messes it up by declaring war against the only civilizations capable of destroying her (Carthage and Persia), but as a player there's an opportunity to peacefully gain control of the world or via the AI's tactic done with player manipulation of the odds, aggressive expansion militaristically.
The Celts storm the world with their Gallic Swordsman, cheap units capable of launching an endless horde on their enemies, capable of coming in and getting out.
The Goths storm the world with their Teutonic Warrior, capable of launching an endless horde on their enemies of cheap, strong units--undisciplined, failing in the defensive, but relentless on the offensive (which is how any player would use them).
The Scythians storm the world with their cavalry, capable of utilizing hit-and-run tactics. (In the original scenario, their riders had an unlisted property of treating hills and mountains as if grassland--I upgraded this to be all terrain as roads. As I found out the hard way, "all terrain" doesn't just mean friendly/neutral/no territory terrain; it also includes terrain controlled by someone you're at war with so this buff was rather notably stronger than I originally thought!) Hordes of horsemen swarming, endlessly, even better at hit-and-run than the Celts, but utilizing it in a different way.
Even decisions that I to some extent regret--notably, terrain modifications which massively amp up shield/food production--have become an asset to the scenario, since I upped the size of a town to 10 rather than 6, and city up to 24 rather than 12. (And frankly, when it comes to that size, I always found it annoying that you had to have a metropolis to have every tile in a city be filled; now you don't!)
I still have alllllllllllllllllllllllllllllllllll that work to do and this doesn't even cover most of the changes.
How I increased turns to 250, made percent of terrain 50% (a number which is actually challenging to achieve! Not impossible, but an actual real challenge to get, rather than something where you're struggling to try and avoid triggering too early which is what 20% was for me), population up to 65% (which frankly is a bit low; I should set it to like 75% to match the difficulty of terrain at 50% but whatever), the added police and civil engineer (not that I need them since corruption is way, way down on Chieftain and due to a perfect storm shield production is through the roof), the whole second era's worth of techs, the increased ease of cultural conversions (I looooooooove culture-hugs; regardless of game, it's my favorite type of tactic and the cousin of the turtle tactic I am so fond of where you expand via defense rather than through offense), enabling Espionage (because c'mon man that was a shortcoming of the original scenario in my opinion; don't pretend that time period didn't have spies because it VERY NOTABLY DID HAVE THEM in some rather famous cases and in warfare that's actually more important than normal to have!), a few general settings modifications, governments, resource values, terrain values, buildings/improvements/wonders, units...
...But this can give you some sense of the type of aesthetic I'm utilizing. A combination of multiple games covering the period (one recentish addition was adding a few things flavored off of Zeus/Poseidon), some inspiration from myths (I tried to keep this at a minimum and mostly in the form of, "you can think of this as allegory meant to invoke the image of the myth rather than literally being it"), some rather questionable and debatable historical evidence/facts/etc. borderline outlandish speculation which are meant to be artistic liberty (for instance, I gave the Macedonians a Hidden Nationality unit called the "Sea People", because ancestors of the Mycenaeans are one possible source of the Sea Peoples even though this is of dubious certainty).
Raising both into the past of the Mesopotamia, and into the future of the Middle Ages with some flavor from beyond, but mostly pre-gunpowder. (I had to take some exception there in naval units since the curragh, galley, longship, and dromon are literally the only non-gunpowder units.)
That's what I was aiming to build. And I've built it, and have pretty much finalized it. My seventh playtest is almost complete, and while I do need to make the easter egg harder to obtain (it's a little bit broken and poorly disguised right now), basically all that remains IS the civilopedia which is an extensive project to undertake.
I even managed to mostly fix the eighth luxury. In the city overview it still gives a blank icon, but at least now it is correctly labeling each luxury (whereas before, they were scrambled). Also got it to display properly on the map, albeit the way I did so borked a prior save and probably all prior saves. A comparatively minor thing, one which the fix is fairly simple, I think.
It's just. Kinda falling into place, as something worth playing for me. Over and over again. And when I've finished, and when I've played it.
That'd be one down, at least two more to go. (Fall of Rome and Medieval Ages use basically the same map. So too does Mesopotamia albeit a little further southeast, but that one, not sure if I'd make a new one of.)