WoW's artstyle is more detailed textures, harder shapes, and darker colors. Starting with WoD, the game gradually started moving towards less detailed textures, soft shapes, and pastel colors, but this only really affected the armor design. Environment art was trucking on as usual. In Legion, enemy models started being affected as well. Now it seems that the old environment artists are gone (or at least, the art director is) and now that cheap plastic look has finally started corrupting the look of the environments.