I have already read it. And for me, the problem is really not only the "colour" of the main cast. It's a concern that actually seems quite secondary to me, in the sense that it can be justified by the lore (and by the cultural tendency, in Japan, to distinguish a main character by his or her hair colour).
If you want to introduce diversity, you might as well go all the way and kill two birds with one stone: change the colour AND go beyond the "wax figure" aspect.