When highlighting/colouring a widget is accepted as an enhancement, the next logical step would be to allow the same on dashbooard level. It would be brilliant if not only the fact that one widget changed state drives the dashboard state. You can define a logical rule how their state will be taken into account to drive the change.
E.g. Dashboard changes state/colour when all 3 widgets change state (widget1 & widget2 & widget3) or 1 of 2 incl. the 3rd (widget1 | widget2) & widget3.