I thought something while making the economics section of my nation sheet and then looking at other people's rolls. About the "unique resources" thing, does it mean that only that nation will produce dye, incenses, etc. or does it mean they simply make it better? Since if that is the case, I'd like to propose an easy system of grading trade goods:

- Unique Grade: This is meant for the nations "unique resources", they are generally more expensive but they are great at what they do (ie high quality timber allows you to make better quality ships)

- Quality Grade: A middle ground between quality and quantity, items aren't too expensive but they aren't quite as good as Unique grade items (ie Excellent grade Critus will make your navies more combat effective by 10% (just a number) while Unique grade citrus boosts it by 20%)

- Standard Grade: The cheapest quality but not exactly "state-of-the-line", Standard Grade is meant for times where mass production is need and quality isn't (ie you need metal for troops, but you don't have too much of your own so you import tons of cheap metal to armor you men quickly)

The system also would allow people to have otherwise unique resources in their own lands, but of less quality so there is still value in trading for someone's timber even if you have your own. Nations who don't have to money to spend on high quality resources can trade for lesser grades of the same thing to save money. It would also allow people to trade goods that are typically associated with the culture they use as inspiration so a France-inspired nation could still have wine even if their neightbors have that as their unqie resource but they do not. 
Also, how big is the list for unique resources? Looking at the rolls it seems to be fairly small seeing as how many peopple either share or flat out have the same unique resources across the board. (Dyes and textiles seem to be pretty common for "unique" resource)