Ah, oops. I maintain that I think that access to west African peppers should not affect the price of trade with India. You could say that the small number means that it won't affect the profitability of the Indian trade, but the Indian spice trade crosses an enormously longer distance. There may be fewer locations, but lets suppose I play in West Africa, and I develop huge population centres on a few of those tiles. How much price impact does this have? I don't know, and I'm not sure that I can unless we get word in from the devs confirming that the price difference across the distance being traded around the entirety of Africa actually merits the existence of the trade route, when the good can be found locally, albeit in a smaller quantity.
I don't actually think the similarity matters. What matters is the impact on the trade routes, mechanically. If something existing as a substitute good has significant price impact, then the result in terms of the actions of the countries and the attempts at establishing trade is ahistorical, even if the culinary use might be classified more accurately in some other fashion. The devs have chosen to split the goods up not by type, but by region, and that's so that the regional price difference merit the existence of inter-continental trade, and so encourage that trade by the player and the AI. I would place that as a very high priority.
The central thrust of my statement was not 'juniper is a substitution good for saffron'. It was,
And the geographic lumping of goods affecting trade. The fact that juniper (or any given single good that was traded) does not fetch the same price as saffron, or that it does not fill the exact use as saffron, I think is far less important than whether or not its existence as a 'regional luxury consumption good' that is used mechanically for the same inputs merits its inclusion.
I agree that Persia should have more saffron provinces, so that adjacent regions are incentivized to buy it more. But that doesn't mean that I think the good should, as you put it,