It's been said that one of the aspects of the algorithm change was how visually pleased Google is by your website. Therefore, I assume color has come into play. What if the human reviewers decided certain colors were more pleasing than others?
I've noticed a trend on ecommerce sites that more winners had lots of bright splashy colors on their homepage and more losers had only a couple colors. In particular sites including earthy tones and shades of blue seem to have done poorly.
This may be a far reach but I'm now pulling for anything after what appears to be more and more like a change of total randomness as far as ecommerce is concerned.