First and foremost, I want variety in the art. A distinct lack of uniform aesthetics. D&D is informed and inspired by many different sources. I want the art to reflect that, and it would be nice if those artworks were produced by a diverse group of artists.
I want some wit and whimsy, too. Like we had in the AD&D-era. Though I suppose this could be covered under "wants variety".
Also, some naked, or at least partially-clothed, un-realism.
And while a bit of "cultural clarity" would be fine, I also want images that shock, confound, and delight, basically art that don't fit neatly into overarching systems, art that scribbles out of bounds (like Cy Twombly after bingeing on the Silmarillion -- well, perhaps not) .
Let's have a little wild rumpus, shall we? And not just illustrations from an imaginary survey course in Dwarven architecture.
In the end, it's not a bad list... I liked the mention of good composition and looking to the past, but I can't shake the feeling it's a guide for a book full of art I wouldn't find very interesting.