This thought has been kicking around in my head for some time now, and it just came up again. Some of the cards from the base game are written in such a way that they don't consider the expansions. For example, the Hex spell. It states, "Place this card on any space in the Outer or Middle Region...." And there are other cards like this one.
Such a wording prohibits this spell from being cast in any of the corner regions. The original intent was to keep it from being cast on any space in the inner region.
So perhaps it is time to update the wording to something like, "Place this card on any space in any region (except for the inner region)...."
House rule, for sure.