Here are some ideas and things that I would like to see come from the Caravan Arc. Most of this is my interpretations of how to do the things Toady has already said are the aim of this arc. I address this to the makers of the game primarily, but I'd also like community input. I think that the community has a lot to say, both in agreement and disagreement, about the Caravan Arc. I've split this up into 5 sections and a very broad summary at the bottom. If you don't want to read it all, don't feel free to skip around, skim or only read the parts that interest you.
Global vs National vs Local Economy:
A main aim of this series of additions is to implement some sort of global economy based on supply and demand. To make this work well, its apparent that things like item/material are to be tracked at both a global and local level. Every city, village or whatever should have a more or less objective sense of supply and demand; which ultimatly pools together to form the nations needs. Even if its only a rudimentary system of checking biome and stone layer info, a local site should have the most definate supply/demand, which would all go to changing a civilization's s/d (I'll abreviate for supply/demand). From that, civilization s/d should again pool into a global economy; as it did from local to nat'l. This 3 leveled system, in my opinion, best allows for a realistic application in game that varies appropriately on the situation. Generally speaking, trade caravans would probably take their nation's s/d into account almost exclusivly when purchasing goods; and slightly the other s/d's (for maybe they're going to sell your stonecrafts right away to some elves who don't mine, for example). When selling, they probably will take into account their knowledge of your s/d and trade agreement from last year (if these will still exist as they are now). As for Adventuring in towns/cities, shop owners should strictly take the local s/d; more or less disregarding what other civilizations and far away towns will pay. Shops also should prefer receiving money (see currency below) far more than the "xsmall racoon leather mittensx" and such that can easily dumped on shopkeeps in return for valuable armor. As for leading caravans as an Adventurer, the global economy is where its at. Actually, it should be about using all three to your advantage. See a human villiage touching a desert? Go there and grab some of the cheap glass crafts that they should be cranking out, only to sell them to that dwarf civ in a far north mountain range as expensive luxieries. Generally speaking, geting it right, in my opion, is working with a system like this, and playing around until it fits just right. Also, keep in mind that this shouldn't necesarily be a solid, concrete "Ok this is this and that is that..." mentality when introducing it, but it should be understood for best reception.
Making Trading in Dwarf Mode More Interesting:
Right now I see 2 distinct areas that one should address in this topic. Firstly, Races. As of now, there isn't much difference between races in trading caravans. Outside of the elf-wood thing, players probably only look at the differences being that humans give a little of everything, dwarves give armor that fits, and elves occasionally have an elephant or something. I suggest fleshing it out a little more. I see humans being more imperial and buisness-y; they bring lots of finished goods and generally expect money (again, see currency) rather than your masterpiece rock earings. I'd argue that this fits well with the mercantile theories in Europe that began to take root around our historical cut-off of 1400s ([history] albiet, it really was more recognized a couple hundred years later, but you can't deny its practice in much of the African colonization in 1300s [/history]). Simply, 1- humans want more money (gold, silver, copper coins) than everybody else and 2- Exports are more important than imports. On the contrary, I see dwarves as the opposite. They are more practical than theoretical; akin to their habits of hoarding, collecting tons of the same object over and over, fascination with crafts and tools. They take a more "hands-on" approach to trading; if they see it and think it looks cool or is useful, they want it. Generally, they are willing to give the useless (at least in their eyes) coins they've been minting for that cool, masterpiece copper pick thats engraved with pictures of cheese. Finally, I'm onto the elves. It's kinda hard to pinpoint where they are regarding economic theory; since they attack you (with wooden weapons) if you try to sell them the same kind of stuff, but at the same time willingly sell Cougars and Giant Eagles into a life of violence and servitude. I'd say they are the middle ground in regards to goods vs capital, just with that generous pinch of spice that is elven morality.
The other half of Fort Mode trading is the local supply and demand of your fort. I think that changing how players assess what a fort needs would drastically reinvigorate trading and add dynamics to your own s/d. The best way to do this is to simply give everything a practical use. Everything? Yes, everything. The idea is to keep the player not only dependant on traders for raw materials, but finished ones as well. What I mean is that not being specialized (ie you're producing a little bit of everything rather than tons of a few different things) will keep your fort running, you won't be making much money in exports. On the otherhand, specializing in something with low demand and an already high supply won't make you very much money either, but now you've got tons of cheap stuff and not any of the other necesities. Currently, it feels like your fort is the only one that actually makes things; while everybody else just stockpiles metal/cloth/wood/etc and gives it to you, so you can make those things. It probably seems hard and trivial at first, but really would impact how players interact with traders. I'd say start with making new clothes a requirement rather than a luxury. Severe injury from the cold and dibilitatingly unhappy thoughts should force players to either buy clothes or allocate a considerable amount of their workforce to clothesmaking. Crafts? There's not a lot to do here as of now, but perhaps make wearing earings/crowns/bracelets/rings/etc much more commonplace, and almost a necesity amoung the dwarven aristocrats. Toys should be especially sought after by children, and again, I'd imagine a kid with no toys to be a pretty unhappy kid. Maybe goblets should be required to drink from a barrel? (however that might be going a little too far) Instruments will probably get lots of use when art and music gets implemented more deeply. Hey, maybe even add a building where the player can manually store masterpieces/high value goods/artifacts that can shoot up the value of rooms or even serve as a museam-meeting place. Hell, it doesn't really matter what way you go with this, I just want to make the point that players only buy stuff they use or are needed. As of now, anybody whose been in a fort for more than a few years pretty much only requests metal bars and tanned leather. I'd like to say that this paragraph is definatly going to be the hardest to implement well without radically changing much of Fort Mode as we know it. This should be more of a long term goal that you can address at your liking. Just know that I think this kind of stuff will ultimatly add endless amounts of immersion factor and dynamic gameplay. This generally isn't Caravan Arc stuff, but it's definatly related I think.
Currency:
A big part of trading and economy throughout history was the concept of currency. Although bartering was fine and dandy, generally, the sooner real-life civilizations adopted a common currency, the more powerful and rich they became. There is coiniage in Dwarf Fortress, nevertheless, it's essentially a neglected aspect in the game. Coins of all kinds of origins and materials clutter up Adventurer's inventory and cause hauling nightmares in bustling fortresses. I realize that this is a stacking/pathfinding issue at heart, I see a way around it. What if your fort's stockpile of gold/silver/copper coins wasn't owned by dwarves, but rather a communal treasury (managed by the treasurer)? This communal treasury (or c/t, I like abbreviations) could hold all of the coins that your fort owns and has minted. I see it as a well secured, chest-filled, coin stockpile-using, kobold-tempting room of importance. When traders come, you haul some of your treasure up to make purchases, and/or haul your profits back into it when they leave. To keep things simple, I think that coins should all be equal at this point in development, meaning that all gold coins (regardless of place or date of minting) are the same value; ditto for silver and copper. Although not eliminating the current barter system, this will add a whole new dynamic to trading. It probably will make getting everything you want a lot harder, which is good. It makes us players think about trading.
Consider this:
"Hmm, I'm relying on my leather imports from the humans, but their liason seems to mostly want coins from us, but I don't have any..." *Dwarves Arrive* "Oh, okay, they seem to want to buy stuff, lets see, what can I sell them?" *uses money to buy leather* "Now I'll makes armor for my army, and maybe I can sell the extras..." -Newly Enthrawled Player
My point is that currency really shouldn't be optional for trade dependant forts, rather something to watch over and maintain or suffer the consequences of FUN. But what about ownership and individual dwarves? Simple, make them use the "credit-card system" that's used in current, coinless forts. I believe it's pretty damn good, and many players opt to use it rather than mint coins. Although it doesn't seem 100% realistic, it does play into the more communal culture of dwarves versus humans (or hell, why not just pretend they're carrying around coins in their pocket for now?). The other affect that comes from this system would be a sharp increase in the value (perhaps not ingame material value, but definatly the subjective value of the player) of gold and silver. Whether it's good or bad is up to you, but I thinks its pretty damn realistic (just look at Alaskan and Californian as well as the New World Gold Rushes). Personally, I'd like to see this more than any of my other suggestions, mostly because flooding caravans with useless goblin mittens and shoes and the ever-so-easy to make rock craft is the only efficient way to get a steady stream of raw materials.
As for Adventuring traders, what's a better gauge of your progress? Treasury, of course. Set out to be the richest human/dwarf/elf/whatever in all the world. Oh yeah, and what things always target trading caravans? Goblins and Theives. But what are they trying to gain from that? Fighter skill? No. Being able to take all the goods you're transporting? No, they can't carry all that crap. They want your copper, silver and gold!
Fort Significance:
With all this new s/d stuff, it would seem plausible that as an expedition goes out, it's obvious that the world's economy will change. Maybe give us some simple story/lore based options based around the s/d. It'd be pretty cool to play as the 7 dwarves who were sent to a remote desert to found a glass-making colony. Since there is high demand for new glass goods, the dwarves send you out into incredibly rough landscape to make what they can't, only promising a supply line (maybe in the form of extra points when making an embark profile? Idk, just an idea) and a guarenteed market for our bigest export. Then continue on, cranking out craploads of glass products, until the shady humans come with a seemingly benign offer for your goods, causing struggle between dwarf and human. Oh, and bonus points if glassmakers, or whatever pertanant labouror, come much more often than normal. This is more of a abstract idea that I had once. Unlike the others that are more "here's what I think will work best...", this is more of a "wouldn't this be cool?". Hey even being able to see the status of the s/d before embarking would be great, since we could voluntarily do this kind of thing.
Misc./Conclusion:
Generally, this has been just about my entire idea of the perfect DF economy system. Uhmm, oh yea, I should also point out a few things to avoid. While I said humans should tend to give better deals when you import from them, and dwarves the opposite, you should avoid simple linear/percentage based stuff. It's all too common in mainstream RPGs to have uniteresting trading. What is usually the case is something has a base value (let's just say something is 100 gold) and all the prices are simple percentages of this. Shopkeepers would probably sell it at 110 gold (110%), but when you sell it to them, you only get 70 gold (70%). Its this kind of pricing that you should avoid, at least keep it out of long term goals. What else did I want to say... Ah, pleeeeease don't forget skill tokens/skills. Having an appraiser with the right social skills should make all the difference in getting a good deal. For the Dwarf Mode trading stuff, its just a matter of making self-sufficiency very difficult and adding direct or indirect penalty for flooding markets. I don't know if it would work, but perhaps a purse/coin pouch could lessen the coin-hauling problem. I guess it'd be like a regular bag, but only for coins, and stores them like seeds. I don't know how it currently works, but when traders bring armor/weapons and other important things, they're almost always either no quality or something a little better, but covered in price-raising engravings and adornments. While cool once in a while, I feel that users would be more likely to buy quality-dependent items like armor if they reliably came in better quality. Players, especially veterans who tend to micromanage more often, don't want to buy low quality armor now, since they can just make near perfect (and vastly superior) ones by training a dwarf for a few months or with a lucky mood. I think it would be absurd to say that a player's fortress is the only one to make anything better than "well-crafted". Masterwork Steel armor weapons should be fairly available, really freaking expensive, but available. One last thing: "small" armor really shouldn't be a trade commodity. I suggest just making any worn goods with that "small" qualifyer should be more or less worthless, even when made of giant cave spider silk. Everyone's basically at war with the goblins, so it's not like the humans are going to make a profit by selling it back to the goblins.
Summary (also a tl;dr):
-Local supply and demand should affect local prices as well as a collective National supply and demand. National supply/demand affects prices between two sites; and also collects to a global suply/demand etc
-Make players more dependant on traders, by making more things necessary.
-Make races more diverse in regards to trading
-Minted coins should be the blood of economy by taking a more and more important role in trading/wealth.
-The communal fort as a whole should own coins, not individual dwarves; thus becoming a valuable trade comodity
-The credit card-like system of individual money stays as the only method of personal wealth tracking
-The economics of the world should be viewable before embark; as to influence site descision in favor of demanded raw materials
-Generally, trading without putting much thought or strategy should only let you just get by. To get wealthy, players must think and plan ahead
I know this is a ton of stuff I just said, and I probably sound pretty arrogant right now (since I'm all like "Here's my idea, you must use it...," even though its not intentional). I realize that this is your game with your vision, but I kinda just wanted my whole two cents on economy. Real world economy, particularly the history of, is something I find really interesting and I really have read a ton about it, so I'm not just pulling this out my rear end. Although it may seem demanding, I am in no way trying to make you do something, just giving lots of input as a fan of this game.
Oh, and I'd like to hear from the DF community as well. Like I said, please critique, suggest, compliment, oppose, tweak, reword, whatever; I love hearing what people think about my ideas. Feel free to post your own spheals on the economy. I feel that if we all get this discussion centered in one place, the more likely ideas can be shared, improved and even implemented.
Wow that was long... I feel like I just wrote a treatise on the economic structure of fantasy worlds. If only Dwarf Fortress was a college course...