What's changed in the past few years is AA's approach to severe weather events.
Trying to "just get thru it" always seemed to leave a huge mess, with crews out of position (and time), aircraft out of position, more people stranded in the hubs needing hotel accommodations, and the wheels would fall off the bus about three days after a weather event because of all the maintenance items and time-based checks that had been deferred.
About five years ago, maybe longer, AA stopped trying to limp thru ice storms or snow events, and started implementing larger cancellations, with the intent of leaving the airline in a position where it could recover. That included having ways to adjust crew scheduling and trying to recover sequences where possible, and leaving aircraft in cities where maintenance could keep up with clock-driven checks.
Add to that the new tarmac rules, and you wind up with more cancellations. Airlines get penalized for trying to operate when conditions suck. They don't get penalized for canceling flights, however. Lots of studies have come out in the past two years showing this "pro-consumer" law's effect on cancellation rates.
It results in some bad PR, but hey, the operation need to come ahead of media attention.