There are so many ideas floating around in here, its really great. Whatever choice they make, I hope it accomplishes a couple of important things well; giving deep and rewarding economic gameplay, and strategic economic choices for the player both in their own empire as well as in their dealings with other empires.
What I think is important:
1. There should be 2 types of resources, raw/natural (wood, metals, grain, etc) and manufactured (weapons, potions, etc).
2. Only natural resources should be created automaticly. All manufactured resources should be created as demanded by the player.
3. Once a natural resource has been processed by a town near that resource with the proper infrastructure, the resoucre should then be available to all towns.
4. Stockpiling and organizing resources should be straight forward.
5. Even though all the components of an item are considered resources, in general the player only worries about the finished product he wants produced. Whether that is an elite soldier with a +2 magic sword, or 20 magical potions.
As long as only natural resources are created automaticly, you can choose to create and stockpile 100 shortswords for a rainny day, and don't have to worry about the AI wasting your iron to do so. If done right, this really keeps the entire process simple and transparent to the player, but if you'd like to you can really get into the micromanagement and reap the benefits of doing so.
For instance: Lets say it takes 3 turns to make a basic infantry unit, with one turn of that time being used to make their spears. You can go to a town, and tell it to make the unit and 3 turns later you have one ready for action. If you had pre planned a bit for the need, you could have made the spears ahead of time, and when you needed them moved the stockpile to the town, and 2 turns later you'd have your unit. The time it'd take is basicly the same, but at the time you need them you get that infantry unit out quicker. The trade off being, you could waste the natural resource without ever making use of the item, and if the stockpile is in a captured city it falls into enemy hands.
This also lets you choose between trading, say, your iron or your shortswords. On one hand you're giving away weapons, on the other you don't know exactly what they'll do with the iron.
I just hope the economic system gives me the ability to be creative and flexible without the obvious headaches. I'm interested to see what they decide to do.