A very nice feature to have on the Dataviz gauges would be events for when the value changes from one range to another.  For example, if I have a gauge with range thresholds at 10 and 40, it would be nice if an event gets triggered when either one of those thresholds are crossed in either direction.  Let's say 0-9 is green, 10-39 is yellow, and 40+ is red.  If my value goes from 9 to 10 the gauge should raise an event that gives me the current range I'm in so I can act on it.