The graph provided by the link at the bottom of creating a new notification policy, "show this notification in action in a graph," is interesting I guess but what I'd really like to see is is a graph of some selectable amount of time graphed for a selectable performance counter, marked with when on the graph notifications WOULD have been sent.  

In the linked example, the red line and temp values are actual historical data from a specified timeline in the past, and the shown notification triggers are overlaid on those values to show what the notification timeline would have looked like for a timeline had the notifications you're currently making been in place already.   A visualized dry-run on some real world data!

This would allow post-mortem analysis to determine, for sure, whether what DID happen in a certain event would have been caught by this notification.    Just thought others might find this an interesting tool as well.