Making certain planets better at producing food than others would allow for some efficiency gains from food trading. The number of people working in agriculture would plummet empire-wide. You would end up with some sort of globalization and blockades and wars could lead to supply chain issues and starvation. This could lead to quite some hyper realistic game mechanics.
In my opinion, from a realistic perspective, it makes very little sense. No world would allow itself not to be sufficient in the basics you need for survival. You never know when the next shipment of resources will come, it would be very risky. Societies in general also develop much better when they are more or less self sufficient in most basic technologies and industrial products, at least in reality. Trade of course is still important as it produces huge excess in wealth and knowledge transfer. But even in our world the poorest and less wealthy countries are those with very little self sufficiency in both industry and natural resources, these societies are also very dependable on others and very vulnerable to changes in the global trade network.
In my opinion Aurora are pretty realistic in this sense as it relies mostly on trade for luxury items. Although I do think that trade should increase colonies wealth income as that is usually what trade does.
But then again the economy in Aurora are quite abstracted and not very detailed aside from TN resources which in no way are consumed or used by the population at all, that is only for the state to worry about. I wish that TN material was a bit more like in Distant Worlds, that the state needed to compete with the population for and civilian merchant fleet for TN resources. If a world is blockaded and they can't consume the TN resources they need their wealth level should drop significantly as well as their political stability modifier over time. This would also be good for role-play as a world that does not get enough TN materials would suffer political instability and eventually you would break it if into its own entity, it would declare independence in order to secure what it needs by itself.
You now could also use the civilian ships to move TN resources... each world you simply would set a demand level and the civilians would try and satisfy that by moving the resources. Civilian mining complexes also would get a different meaning in the game as they would always produce the resources.
I also think that all resources probably should belong the to civilian economy and the state need to pay for it when they use it in wealth. You should then be able to tell a certain colony to only consume say 80% of their needs, but that would then effect their wealth and political stability, you could oppress it with military if you wish... but it would be a way to play more oppressive regimes or something you would need during wartime to use the TN resources for building military ships rather than consuming it for wealth.
In my opinion this would be more interesting than introduce something as insignificant as food, something that is just a measure of energy and basic none TN materials.