The Smoldering City trade route should always have the option to buy Packs of goods that you sell, both for theme and balance reasons. It would make trading more predictable, and provide various paths to more easily turn different resource booms into profit.
Right now there's little reason to optimize for Packs unless you're fulfilling an order.
In today's update, we increased likelihood of packs being bought by other settlements via trade routes (as well as their price), and the Citadel now buys all pack types (aside from Provisions). It can still request other items, but you should see pack more often (of course, if this isn't enough, we will iterate on it in the future).
I do think that, in the current build, packs are an under-utilized mechanic.
Their only purpose is to complete orders, occasionally complete glade events (though often feel woefully inefficient at doing so), and occasionally to sell to traders or routes when specifically demanded.
Meanwhile Packs of Provisions have a specific utility to them, while Crops, Building Materials, Trade Goods and Luxury Goods do not.
So to have a consistent demand for packs would at the least make it worth setting up consistent pack production and make pack recipes more valuable.
But ideally, I'd love to see packs all be given a secondary utility to them, similar to how Provisions fuel trade routes.
Perhaps using packs of Building Materials as an alternative currency to constructing buildings faster and more efficiently, as an example.
Well, packs do have an interest with merchants who tend to buy them for lore money than they would for the amount of raw reources needed to make them, usualy..
That said, I like the idea but may I suggest a variant that would go well with the loe (the fact the biurning city alway needs more resources and that's what the colonies are for) and a bit of idifferent lecanic: Why not have the burning city alway be ready to take packs in exchance of a decrease to imatience rather than jsut amber ? Make sense, a colony produce packs for the city, the queen is willing ot let it go longer, no ?