Aside from the nine Conquests scenarios, the expansion also includes 7 new civs, plus one bonus civ which can only be accessed through the Editor. Before getting into the new civs, however, it would probably be a good idea to start with describing the new civ traits and what exactly it is that they do.
Agricultural civs have a number of distinct advantages which will probably make this a very popular civ trait. All cities under agricultural civs get +1 food in the center tile; that is, they produce 3 food in the center tile rather than 2. This bonus food is canceled out by the tile penalty under despotism EXCEPT when cities are settled next to rivers. Agricultural cities on rivers will still get 3 food in the center tile even under despotism, which greatly speeds up expansion in the early game. All other cities will see a significant boost in growth when switching over to a non-despotic government around the beginning of the Middle Ages. Agricultural civs also get half-cost discounts on a few buildings relating to agriculture: acqueducts, hydro plants, and solar plants. They originally also got half-cost granaries, but this was definitely a bad idea and was quickly discontinued. Finally, Agricultural civs also have the unique ability to get extra food out of desert tiles. Specifically, an irrigated desert tile provides +2 food instead of +1, thus essentially terraforming it into a plains tile. Note that this does NOT apply to floodplains tiles, only desert ones. It used to apply to floodplains as well, but this was overly powerful and resulted in pictures like this:
Yes, that floodplains wheat was pulling 7 food/turn without railroads. Ouch. Good thing that's no longer the case. Agricultural civs thus potentially can be very strong indeed, since growth is the single most important factor in Civ3 and they get an extra food in the center tile of every single city. This is partially canceled out by despotism, but the designers left a loophole in the whole river thing. I did NOT support that move, and I think it will definitely be abused, with players re-rolling every map when playing agricultural civs until getting a river start. Between the extra food, ability to reclaim desert tiles into plains ones, and half-cost acqeducts, agricultural civs definitely have a lot of potential to play around with and are worth a serious try.
Seafaring is the trait I am least satisfied with. I liked the way it was previously implemented, but it changed in later patch versions in its current form which I think emphasizes the wrong kind of gameplay. Seafaring civs get +1 commerce in the center tile of all cities founded on the coast, much like how commercial civs get extra commerce there as well. Seafaring civs also have something like a 90% chance to start next to the coast on the map, so that they will be able to make use of this ability. They get half-cost buildings which relate to the sea: harbors, coastal defenses, commercial docks, and offshore platforms. Seafaring units also get benefits to their naval units: their ships are less likely to sink in sea or ocean tiles and all ships gain +1 movement. These abilities are much like naval operations in general in Civ3, useful on archipelago maps but almost worthless on a pangea. Certainly these abilities are nothing to write home about.
So why is Seafaring the most popular trait among those players who have beaten Sid? It's for the same reason why I think the Seafaring trait is poorly implemented: the trait seems designed to benefit "suicide" curraghs and galleys more than anything else. It goes something like this: set up an archipelago map, which negates the Sid expansion bonuses. The player then uses cheap suicide curraghs to contact all the other civs and stay caught up in tech throughout the early stages of the game. Since the rules of contact/map trading have been changed in the expansion (contact trading pushed back to Navigation and map trading to Astronomy), the player can be in contact with all civs while the AI civs remain clueless to one another. Needless to say, I don't like a civ trait which seems designed to promote suicide curragh runs and do little else. I hope that this trait will be adjusted in future patches. Now onto the new civs.
Sumeria: The Sumerians are Agricultural and Scientific, a combination which seems to work fairly well at balancing growth and city development. This may prove to be a very popular civ for players who like to expand quickly early on and also reap the trading benefits of a free tech at the beginning of each age - to say nothing of the half-cost science buildings. This civ offers a lot of potential to be played in different ways. The unique unit (UU) is also a pretty strong one, though definitely only useful in the ancient age. The Enkidu Warrior is a warrior UU, costing 10 shields and having an extra defensive point to make it 1/2/1. It also upgrades to the pike, making it essentially a half-cost spearman which can be built from the start of the game. The Enkidu makes a great defensive unit, and at such a cheap cost should be able to pillage enemy civs with ease if an early war is encountered. The big downside is the ultra-early golden age and the fact that the UU doesn't add anything that another unit can't already do, only making a pre-existing unit cheaper. Still, it's hard to argue with a civ that does this many things well, and I believe the Sumerians will be quite popular upon release.
Hittites: These guys are Commercial and Expansionist, giving them the traits that the English used to possess in standard Civ3 and PTW. This means that the civ trait benefits for the Hittites will be minor, and much more subtle than some of the other ones. Exploration is more important than ever now that contacts and map information can't be traded until well into the Middle Ages, so the expansionist trait will help the Hittites there. And the commercial trait tends to pick up as the game goes along, which balances with expansionist decently. Still, the Hittites are not a power civ when it comes to their abilities and it's important to keep that in mind. Their unique unit is a modified chariot, a 30 shield 2/2/2 unit which is essentially a horseman with an extra point of defense. The Three-Man Chariot is still a chariot, however, meaning it can't cross jungle/mountain/marsh tiles without a road. The UU is certainly an all-purpose one, but it doesn't do anything especially well. I'd have to say that I would prefer both the Egyptian War Chariot and the Iroquois Mounted Warrior to this unit. The Hittites are an interesting mixed bag, but don't looks for them to be one of the strongest civs in the game - they aren't.
Netherlands: Ah, the Dutch. With the combination of Agricultural and Seafaring, this civ created all kinds of problems in the testing process. If you want to try out both of the new civ traits, here's your civ. Back in earlier versions of the game, Seafaring used to confer a +1 food bonus in the center tile as well for cities on the coast, which in the case of the Dutch produced a massive growth effect called the "food bomb." In the current game, the Netherlanders still get the benefit of faster growth from agricultural, but this doesn't always mix well with seafaring. Like most other seafaring civs, the Dutch will be at their best in an archipelago setting. That doesn't mix too well with the agricultural trait - better suited for large continents to be expanded across - so they are a bit of a mixed bag. The unique unit is an excellent, if somewhat uninteresting one however. The Swiss Mercenary is a 30-shield pike with an extra defensive point, making it 1/4/1. When you consider that the 2/4/1 musket costs 60 shields, you can begin to see what a fantasticly cheap defensive unit this is. The Swiss Mercenary must rank up there with the Hoplite as the best defensive units, pound for pound, that exist in the game. The UU golden age is also very well timed right at the beginning of the Middle Ages. The Dutch therefore have somewhat curious civ traits combined with a very solid unique unit. Experimenting will be needed to test the true value of this civ; it probably will be very much situational.
Portugal: The Portugese are the quintessential exploring civ. They are Expansionist and Seafaring, meaning they can build both scouts for land and curraghs to explore the sea right from the start of the game. No one can scope out the map better than the Portugese, so if you enjoy pushing back the blackness on the map, they are the civ for you. Unfortunately, their civ traits do not combine all that well; expansionist works best on large pangea maps where scouts can grab lots of goody huts while seafaring, as always, is strongest on archipelago maps. And true, the Portugese can scout the map the best, but once they do that they have little else going for them. Still, their traits should help them stake out an early lead that they will have to try and hold for the rest of the game. Their unique unit reflects this exploring mentality; the Carrack is a 2/2/4 modified caravel which does not sink in ocean tiles. For the same cost of 40 shields, the Portugese get a ship which has an extra movement point and an extra attack point. Again, the primary purpose of the Carrack is to explore ocean tiles before any of the other civs can safely do so with their ships. Just think "exploration" with the Portugese, and you'll know all you need to about them.
Byzantines: This is another civ with somewhat mixed abilities. The Byzantines are Scientific and Seafaring, a combination which could play out in many different ways. Scientific is a trait which has very little to do with Seafaring, but perhaps the combination will play out well, I just don't know. When you consider their unique unit though, the Byzantines are obviously intended to be more of a Seafaring civ than a scientific one. The Dromon is a galley modification with some greatly increased stats; it is 2/1/3 and still transports 2 units, but has a bombardment attack as well at strength 2/1/2. The Dromon's bombardment is lethal to sea units, so this unit clearly has the ability to sink all ancient age naval units with ease. On an archipelago map the Dromon could be absolutely dominant in the early portions of the game; on a pangea map it would be almost useless. Clearly the parameters of the map to be played will determine whether it is the Seafaring or Scientific trait of the Byzantines which will have to predominate in each game.
Inca: The Inca are a another civ well given to exploration, only on land instead of sea. They are Expansionist and Agricultural, two traits that combine well on large, pangea maps where you can flood the map with settlers and scouts. Agricultural will suit the Inca well in expansion, while expansionist will let them use their unique unit scouts to find either enemy civs to attack/trade or terrain to place those settlers. Their UU is the Chasqui Scout, a modification of the standard scout which went through many, many changes in the testing process. The Chasqui is currently 1/1/2, costing 20 shields, and ignoring movement costs for hills and mountains (like the keshik does in PTW). At double the cost of a normal scout, and too expensive to be used as an attacker, this unit really doesn't have much of a purpose. I MUCH preferred the earlier version of the unit, which was 0/1/1 with the treats all terrain as roads ability. That was a true UU scout; what we have now is a unit that serves no real purpose and is too expensive to serve its role as a scout. I'm still hoping that the Chasqui will be fixed in a future patch. Until then, the Inca should have to rely on their civ traits and not their unique unit.
Maya: The Mayans are probably going to be the most popular of the new civs. They combine two strong civ traits, Industrious and Agricultural, and have a pretty sweet unique unit to boot. With fast workers and increased food production, NO ONE will have a faster growth curve than the Mayans. Granted, they don't get many shield discounts on buildings, but does that really matter if you have more cities than anyone else on the map? If you can get a map with a river start, this is a fearful combination in action. The unique unit Javelin Thrower is no slouch either; it is a 2/2/1 archer modification that costs 30 shields. This is the same as the Babylonian bowman at a cost of 10 extra shields, but the Javelin Thrower has the ability to enslave the enemy after a victorious battle. 1/3 of the time upon winning a battle, the Javelin Thrower will produce a captured worker, completely for free! Take a look:
Don't forget than any enslaved workers will work just as fast as a standard worker, since the Maya are an industrious civ. Now on the higher difficulties it may not be feasible to sink a lot of shields into an archer unique unit, and the golden age does come very early, but the ability to get free workers is just too powerful to ignore. The Maya not only have the civ traits to expand very quickly, they also have a good reason to go to war early on to try and produce some enslaved workers. In short, there's a lot of potential for both peaceful and warrior games here. If nothing else, the Maya are a fun civ to play as!
Austria: The final civ is the hidden one, the Austrians. Since Civ3 has an encoded limit of 31 civs, to play as the Austrians you must go into the Editor and enable them yourself, replacing one of the other ones. Still, they have leaderhead graphics and the whole works; they really are an actual civ. The Austrians are Militaristic and Industrious, just like the Chinese, a good combination definitely designed for war. Their UU is the Hussar, a cavalry modification which gets an extra point of attack to go to 7/3/3. This extremely powerful unit is probably the reason why the Austrians are a hidden civ. And if you'd rather not go through the hassel of using the Editor, you can always play as the Austrians in the Napoleonic Europe Conquest.
The addition of the new civ traits has resulted in a shuffling around of traits for some of the older civs. This was definitely a good idea, since the original six traits were getting REALLY repeated beforehand. BreakAway did a good job on the whole of matching up traits logically with each civ, and although they aren't perfect, it's hard to complain too much with the alterations. If you really don't like what they did to your favorite civ, I guess you can change it back in the Editor. Here is the list of new traits for the original and PTW civs:
Aztecs - Militaristic and Agricultural
Iroquois - Commercial and Agricultural
England - Commercial and Seafaring
Scandinavia - Militaristic and Seafaring
Celts - Religious and Agricultural
Carthage - Industrious and Seafaring
Spain - Religious and Seafaring
The Iroquois were the only civ to swap both traits, but to be honest, Commercial and Agricultural probably reflects them better than Religious (?) and Expansionist. England and Scandinavia in particular now have MUCH better traits for their history. I like the changes on the whole, and hope that people won't be too stubborn about them.
Having reviewed the new civs and civ traits, the next thing to consider is all of the changes to units - both new units and alterations to old ones. Be ready for some long reading; the list of changes is extensive.