How would said resources be distributed? With the number of towns potentially involved, I find it hard to believe that everyone can discuss it and come to an agreement on how to divide them if they win.
I would also be concerned that towns on the same continent may try to win trade to remove valuable bounties that could be at risk of being invaded. (I know it's against the rules to win trade, but they could establish deals with enemies on their continent which would make it much harder to detect than other forms of win trading)
It would have to be restricted who can do this, most likely capitals. Otherwise, it becomes far too confusing and complex.
I like the concept, just think the idea needs some work.
Some quick random ideas of mine. What if once a week a neutral territory on each continent become bountiful but with more resources than a normal bountiful territory. It could only be attacked by those from another continent. We could add extra spice and have 2 inhibs and make it a 3 way fight between all the continents. Could be everyone vs the defending continent but the defenders get unique extra powerful modules? Or do we make it so it's a purely capital thing, where towns choose the capital they want to fight for and only capital territories can be attacked?
p.s. The argument that the 'market is dead' is pretty poor. The resources have a lot of value, which is the point of the system. Just because people are not choosing to sell them for shards on the open market does not mean there is no market for those items. Restricted resources are often traded for other restricted resources and political influence plays a big part.