I would add that I think it would be nice if cards built off the same dataset could "share" a legend on a given dashboard. Meaning that, if it is on the same dataset, the dashboard would assign colors to a given series and that color would stay uniform across the dashboard without requiring me to set up color rules. For example, I don't really care what color the North-East region is, but it would be nice if all of my charts on a dashboard would know to make it the same color. Maybe that is just me being lazy though and not wanting to write out color rules manually for everything...