"Not when I just swap some towns' specializations and they go all "Oh no, my old trade route doesn't work, you've broken everything, it's the end of the word, #literallyunplayable'."
Didn't say that at all, stop being such a drama queen.
A few examples would be there used to be plentiful supplies of salt in Hakkon, now there isn't, there used to be plentiful supplies of iron in the dwarven lands and it was cheaper now that's no longer the case. Many towns/factions still don't seem to have any specialization at all in what they produce the Tolranians for instance don't seem to have any particular theme for what their villages produce and their towns manufacture.
I don't mind that a lot of this is a complexity that will never be implemented because the main focus is the 'war' aspect of the game. If you want a feedback suggestion on it though then find a way to greatly reduce trade good pricing in the buy and sell option based on trade skill and make certain goods more abundant in places where it makes sense for a caravan doing a long haul. I get that it needs to be balanced for looting purposes.
I fully understand that this is not a critical thing to focus on.