As a colorblind user, the WPMU Dashboard is the most unusable product I’ve encountered this year. Tiny icons whose distinctions are shown only as dark grey, green, or red make it impossible to discern state (which is only communicated visually via color). So I have to hover over each icon (15 rows of 7 icons) to figure out if there’s an issue or everything’s good.
If you can ONLY communicate via color for some reason, I would expect dramatic differences in black/white value so that users can distinguish states beyond just the color. E.g.
things that are good/fine/successful would be very light in value (20% grey), fail/alert state is 100% value, and whatever other state might be 55% value. But could also add small checkmark and small X or ! over icons that need user action.