Game tone, in a single line, 'A Player vs Evil vs World experience in a black-grey morality, where nature doesn't want them there'.
I can absolutely see the appeal in much of the modern presentation of the game with a more anime (I know its not anime get get on me folks) or cartoon like style. Essentially the Critical Roll intro.
What I like more however, is the subdued art style. A darker, more classical (imo) tone with a palette that matches it. I want the characters, and world, to be massive, but the palette to be more..simple? I dont know, I'm not trained in art to be able to communicate it well.
I like it when the world, the climate, nature take a very front and center role in how the setting functions, and that it is communicated in the art. Huge landscapes, gorgeous ocean and mountain vista's, lush forests, arid deserts, and dank swamps. The world itself should be a character in the setting.
I want there to be a very real distinction between the supposed civilized world, and the wild one, where the people do not attempt to tame nature, because when they try, its either through their own corruption, or eventually they are broken by nature itself, or those who would protect it.