I kind of like the idea of an "exchange rate".
Basically, the idea would be roughly(!) like this:
- construction of something (a building, a fort, a road, whatever) has a cost in materials, but they can be satisfied from specific materials, generic materials or gold
- let's assume you want to upgrade your fort and the block costs 100 wood and 100 stone.
- you can provide 100 wood and 100 stone - done
- you can also provide 300 wood or 300 stone, because materials can be exchange for each other at a 2:1 rate (or 200 wood and 50 stone, or whatever)
- you can also provide 100 wood and 100 gold, because materials can be ad-hoc bought at a 100-gold-per-100-units price (twice the maximum price the market allows). Or 100 stone and 100 gold. Or just 200 gold. Or 50 wood, 50 stone and 100 gold, etc.
The part about this that I don't like is that it makes things fairly complicated. But I wanted to throw it out there.
