well maybe you right about it should be nation feature but in history nations used tax collectors as a middleman for collect depts. Nations doesnt involved directly to get them.
With that idea i think it would make this voodoo as an imaginary middleman for nations to collect their golds. instead of past tax collectors now we have voodoo for that. i would like to hear more about your ideas.
+1 middle men plus if you don't have any debts to any nations it doesn't hurt you nothing to collect on so why wouldn't you pay your own nation debts it cant cost that much