In order to cap off the month of February I posted a string of non-traditional fantasy images over at my art stream. When I looked very closely it was sometimes hard to determine which images fell on each side of the issue. Even the same iconic character, Regdar, is depicted inconsistently when he is illustrated by different artists. Does Wizards of the Coast provide diverse art? Starting with at least 3rd edition, it would seem so. A lot might depend on how specific does Wizards R&D get in their art orders versus how much is determined by the illustrator.
It was pretty easy, just in the two Player's Handbooks (3e and 4e), to find a wide variety of characters depicted.
I saw a few comments comparing Paizo with WotC. I can't speak to that but what I did learn is that I prefer visual references of characters in chainmail (see below).