I couldn't agree more with your final thought. I assumed there may only be one or two diverted flights in a day, and certainly a handful more during winter weather, etc.
I clearly remember when I finally let my initial prototype run on a laptop for a day and ignored it, an old HP laptop just chugging away parsing flight plan data, plugged in and running too hot in my office. By the next day I had > 20 diversions, with no notable weather, and assumed I had a bug in my logic.
Lots more to do here, including adding some weather details and someday predictive analytics. Thanks again for checking it out and the feedback.