I've noticed this as well. Personally, it really, really bugs me how 90% of the wolf characters in the game are either pure black, pure white, or some shade of grey. Why can't people make characters who are brown?
I think out of all the overused colours, though, pure black characters bother me the most. Grey may be a pretty overused colour, but at least it looks alright. Pure white is pretty annoying, but at least though don't look like a shadow, Pure black characters don't even look like actual wolves.
Like, I can understand making a demon character be pure black, or a character in the Ebony Circle [speaking of which I really wanna join them some time], but when people start making 40% of all the wolves in the game pure black, to the point where they look like shadows, it just becomes unrealistic.
At the moment, I only have one wolf character, but she's dark brown with green eyes [though she has a preset]. Whenever I make a wolf character, I usually make them brown. I don't use black, white, or grey most of the time because those colours are overused.