We were able to round up 5 players for our game, so we used the Western Extension Map, which adds Iberia and western North Africa. I like this configuration with 5 because it removes Egypt and Babylon from the game, and those nations are tough to play despite tremendous geographic advantages, because of their need to build 2 cities early which cripples their population growth. We ended up with Assyria, Thrace, Illyria, Iberia, and Africa in play, which worked out pretty well I thought. There isn't quite as much pressure on space as there is with the regular configuration – most of us were able to keep at least 7 cities up most of the time – but this didn't seem like a major deal.
Figuring out what number of players is the optimal number for Civilization is a little tricky. More players gives some fairly intense competition for Civilization cards since there are only 4 of each type, which is good. On the other hand, more players also seriously stresses the trading phase (as we shall see), as there seem to just not be enough cards to go around. Build too many cities, and you can get rather shut out as large numbers of stacks of commodities are depleted by the time it gets to you. You can throw in the expansion trade cards (Timber, Oil, etc.), but this isn't a particularly satisfactory solution either because it seems to add too many new cards to the mix, and it significantly increases the randomness of the game. That said, they do seem almost required for 7 because otherwise things are simply too sparse.
So at the end of the day, I think I can say that 7 players is definitely too many for classic Civilization. My recent plays have always been with 5, and I've been pretty happy with how well that has worked out. The trading part of the game seems extremely well balanced at that number. At 5-6 hours, the play time isn't unreasonable, and since the game increases in length almost linearly with the number of players, adding more can take it over the threshold from "long" to "unworkable". The only downside with 5 is that you lose the interesting competition for Civilization cards. An idea was floated during our game that when we play again with 5, we should play with only 3 of each regular Civilization card, 2 Mysticism, and 4 Democracy and Philosophy (although the rest of the Civics should have 5 available) to introduce more competition. I like that idea a lot.
Anyway, I enjoyed our game of Civilization, more than I expected to in fact, and I would happily play again anytime. I swore off Advanced Civilization approximately 10 years ago, and since that time I've only played classic Civilization intermittently, and it's taken me a while to unlearn all the things that Advanced Civilization taught me. It's amazing the number of my instincts that are still wrong. And each time I play again, I appreciate more of the subtlety and depth of the original. Heuristics that were simple and clear-cut for Advanced Civilization are all of a sudden grey and interesting again. I love it.
Take the point-value hurdles in the Late Iron Age. Each nation has certain point objectives they have to meet to win, varying from 1200 to 1400. These have to be met with values of civilization cards and hoarded trade goods. I had internalized the fact that these numbers simply don't matter; if you're going to win, you'll have to exceed them for other reasons anyway, so they make no difference when choosing nations. In our game, though, the player playing Iberia won when he could just barely amass enough points to pass by his 1200 point barrier while Assyria, who looked like he was cruising to an easy win, fell just short of his 1400 point target – even though he had a very strong mix of cards, having bypassed Mysticism and picked up very few cheapies like Pottery. In fact, all the barriers in the game (with the exception – for most people – of getting two cities to get out of the Stone Age) are tough, and a 1400-point box at the end is nothing to sneeze at. Even if you ace the Early Bronze Age by getting Architecture and, say, Astronomy, if let your guard down and have a bad round of trading and a Civil War, you can easily get hammered by the Late Bronze Age's requirement for 5 cards. It's great to see an empire-building game where a strong start doesn't give you a huge leg up in the middle game (it definitely helps, it's just not huge, that's all). You have to play well throughout. A corollary here is that getting hit with a lost step on the AST early is bad, but it's far from fatal. In our game, the only person not to be held up was the eventual winner, and it was a very closely-run thing. Of course, you don't want to get held up early if you can avoid it, but again ... it's not the kiss of death it has a reputation for being.
The other thing that impressed me this time was how well the trading worked. Sure, everyone says that the best part of Civilization is the trading, but playing it again, it was clear that both a) the trading is cool, and b) the way it feeds back into everything else in the game is also cool. There really aren't that many systems in Civilization – trading, city maintenance, taxation, civilization cards, calamities – and they all are interlinked, feeding back into each other in important, interesting and surprising ways.
But on the mechanics of trading itself, the simple way in which it works belies surprising depth. Commodities escalate in value in a geometric progression, where the value of n commodities of value x is x * n^2. So 4 Salt (value 3) are worth 3 * 4^2, or 48. There are 9 Salts available in the game, so Salt maxes out at 243 (although on any given turn, not all may be available of course). Each later commodity has one fewer available, so 8 Grains can be worth 256, 7 Cloths 245, 6 Bronze 216, and so on, up to 3 Gold for 81.
Obviously, there are some trade-offs here. Bronze doesn't go as high as Grain, but it gets there faster. The three commodities in the middle – Grain, Cloth and Bronze – are the most valuable, because they both have a high ceiling and appreciate rapidly. Spice (7) is cool, but with a maximum value of only 175, and with fewer people acquiring it due to the difficulties of maintaining 7 cities, it's somewhat less attractive. Salt maxes out at a big number, but it takes forever to get there (9 cards can be worth 243, but only 6 Bronze are worth 216). Also, because you can only hold 6 cards at the end of the round, being able to acquire 8 Salt will be rather painful because you will be forced to spend instead of holding out for the last one next round.
So you ideally want to be trading in Grain, Cloth, and Bronze. Not only do they represent good value, and partial sets are easy to save from turn-to-turn, but it's also not too hard to maintain the 6 cities required to generate them, so there should be plenty out there. But only three people can do this; if two of us are collecting Grain, and we split them, we will each have four grain worth a paltry 64, and will face tough decisions about continuing to hold them until the other is forced to make a purchase by the AST or other factors (thus ensuring ongoing Civil Wars until that time), making a swap that inordinately favors the other player, or cashing out now to buy something less than what we want but to at least get something and let credits and advantages accumulate. Meanwhile, someone who was working in the nominally less-useful Salt probably came out ahead. With 5 players, and only three commodities in the "sweet spot", there is considerable trading pressure.
Meanwhile, the basic incentive to trade is huge. If you and I each have a single Cloth and a Bronze, we both win big when we swap, regardless of who gets what. Because commodities appreciate so rapidly, you can't just sit there. The player who quibbles over five or ten points will be in trouble, because just making the deals is so important initially. So in that situation you should always ask for the Bronze (it's worth more, after all), but all other things being equal you should always take the Cloth and close the deal rapidly if push comes to shove, because moving quickly and scooping up a number of commodities before someone else has time to do the same, causing a painful split, is a very good idea. Just because you aren't playing with a recommended time limit on trading doesn't mean it doesn't pay to be fast. But the incentives to trade weaken dramatically as sets grow in size, because the appreciation right at the end is disproportionately large and so making reasonably fair deals is harder unless we're both closing out sets. Players invested in less-optimal Salt or Spice can extract very nice trades if they can hold out until they have the last Bronze someone is looking for, and players who are having a weak trading turn due to calamities and whatnot and are not expecting a big payoff until later can hold out and make life interesting. Recognizing when you have the strength to start aggressively collecting Bronze or Cloth, and when you should let others fight it out and try to cherry-pick some Spice or hoard Salt, holding your mid-ranking commodities until you can get a sweet deal, is a critical decision.
In addition, while keeping an eye on these mathematics of trading, you have to be aware of your board position. At a basic level, you don't want to be acquiring Spice so much if you know you're not going to have 7 cities next turn because you just drew the Civil War, and so your personal supply is going to dry up. But one also has to keep an eye on what you want or need to acquire, because it's easy to over-trade. There will usually be constraints on what you can buy, typically because you need to hit a target to pass out of an age, desperately need a technology like Engineering, Metalworking, or Agriculture which may not be available next turn, or need to acquire or wait for credits or pre-requisites to kick in (like acquiring Literacy, Law, and Democracy on sequential turns). It's a not-infrequent occurrence to trade heavily, pick up a 6th Bronze, and then realize you are unable to spend it. Given how much money you likely gave someone else to get it, this is very bad.
All this is the main reason I have qualms about the variant trade cards. By doubling the number of commodities in the "sweet spot" (adding Oil at value 4, Wine at 5, and Silver at 6), everyone can basically have their own commodity and the trading falls out in a fairly predictable way, with everyone monopolizing one type. Because the disincentive to trading someone the last couple good commodities that they need has been greatly reduced in most cases (because you can usually get a good one back, too), the balances seem to get messed up. In the original game, with fewer commodities, there is more pressure – and pressure is generally good. Granted, when playing with 7 players, you'll probably need the variant cards just to make up the numbers for dealing out cards each turn.
I could go on with the interesting things I discovered about Civilization getting to play it again, but time and space are limited, so I'll let you discover some of the rest for yourself. Suffice to say, my respect for this classic game did nothing but increase. Check it out.