So, to return to my original point, art in games that is good is often the art that has least ‘purpose’. Generally this means that the art is generative, it came in earlier in the planning process, perhaps it originated the planning process. It wasn’t made to fill a role, it created the context in which other decisions were made.
I’m thinking here about the different approaches to development represented by Games Workshop and whoever is running D&D. (Hasbro? Wizards?) I don’t actually know much about this in detail but I will give you my impressions.
And there shouldn’t be any art in there that does not do that. It’s not like you have to be fair to all the mediocre art that didn’t get in. You don’t have to be complete. It’s not an encyclopaedia or a dictionary, it’s just pretending to be one. It’s something else wearing the disguise of a reference book. A kidnapper dressed as a policeman. The book isn’t here to define all the fourteen varieties of ghost you can find. It’s here to make you feel like there is a ghost in the room, even more, it wants to turn you into someone who wants to make others feel that way. It’s a conductor for a kind of cultic behaviour.