Not any time soon.
which should (if I get it right) ensure that players don't have to worry too much about the day-to-day management of these resources if they don't want to,
This is important which is why i'd say we should limit these resources to trading only, as described in this feature request.
Perhaps for building a better decorated palace or to give ones estate a bit more flare, maybe for an extra fame point or something but nothing essential like building RC's, recruiting troops, repairing buildings or troops or even increasing production or food/gold income.
Not only would it make things to complicated, it would also take over the entire game.
Also it's important to balance the possible income from resources (even though it will heavily depend on how its traded), in order to give players the ability to ignore resources altogether or barley do anything at all with it (if resources stocks stack up in a certain estate one could be given a message and simply sell it off once in bulk for cheap).
Perhaps resources can also use granaries called warehouses for example to be able to keep things in stock without rotting/deteriorating to prevent massive build ups.
Basically we can use many already existing in game mechanics to make tradable resources work especially from the way food works and is traded.
I am not sure if this is practical at all for the devs, but to me it looks like we can 'copy' much of these mechanics to apply them for resources and trade, significantly reducing the work needed.
If unfinished mechanics are already there for resources and resources allocation then that seems to be another convenience.
Also as mentioned by Jevondair, the role of realms and politics/war could be significant.
Realms could even be given the option to put specific taxes on owning resources or the trade of resources as well as closing borders for trade with certain realms (making it illegal like looting with fines and notifications).
But even without wars, this creates a whole mini game for players with 'normal' characters, knights that ussually just follow orders.
