The thing with color has always been that, while color is meaningful to humans, it's not particularly meaning to bots above and beyond just another in/out pair.
Still, it would be a really useful debugging tool, etc. I like the idea of being able to hook up either specific actions or specific sysvars (in/out) to a color readback. Right now bot color is related to genetics, but it wouldn't be too hard to create a dialog box and let users have color come from other sources.