As we know the barn in this game has a limited capacity to hold goods, almost always it becomes really painful to store different kinds materials needed for building, upgrading and expanding. Nobody wants to store it but we have to because we don't get it evenly and as per requirement. Sometimes we have to store more than double of a kind just because we don't have enough of the other kind. Bottom line is that these materials are occupying half of the barn turning the game into a painful and frustrating one.
Hence I request the developers to enable exchange of these materials to make it more interesting and enjoyable. Thanks a lot.