First of all, I know this is way off-topic for this thread, but who's gonna put me in AMwx jail?
That's interesting because at IWX, they are really promoting using "impact-based messaging" and I assumed that this is the mantra NWS wide. Maybe part of the problem is rigidity of following the criteria for meeting a particular product.
For example, at IWX the criteria for heavy snow is 3-5" for a WWA (or 2-4" at the forecaster's discretion), and greater than 6" in 12 hours or 8" in 24 hours for a Warning. In conversations I've had with their WCM, I got the impression that in the past, they may have gotten their wrist slapped for "overwarning" an event. For example, upgrading to a Winter Storm Warning for 5" of snow, even though there were exacerbating conditions such as blowing snow or glaze ice underneath the snowpack.
It seems that with impact-based forecasting, they've loosened up some and given the individual forecaster some leeway in issuing products. Just my point of view, maybe some NWS mets can chime in.