For those who weren't able to watch 'Sup Holmes, Bozon has been explaining the color thing really well. Basically, he had to make the base colors super light and bright (including the clothes and hair, so not just skin) because of the lighting engine used, which can be thought of similar to the Multiply blend mode in PhotoShop. The fairer the skin starts out, the easier it is to light it with different colors as the character goes through different lighting schemes, such as a night area and a fire area.
The intent was never for the final image to be as fair as what was first shown in the Kickstarter campaign, just the base, uncolored artwork. It was due to a mistake and lack of attention that most of the illustrations in the campaign were based off of this base image.
I, for one, am super glad that this explanation has been coming to light.