Good decision to change your flights!!
The "spoke and hub" system that the airlines use to make sure that there are no direct flights to anywhere (yea that sounds like sour grapes) means that if there is a hiccup in the system in the northeast that your flights in the southwest will be fouled up too.
After a very nice WDW vacation many years ago, we were waiting at MCO to fly home and every minute (literally) there was an announcement by each airline saying that flights to NYC were being delayed because of weather. We joked that we were glad that we were not going that way. We flew to Salt Lake and found that our connecting flight would not arrive for over 6 hours (instead of an hour layover) because the connector was coming out of NYC. So we all stretched out on the floor to rest (they finally brought us blankets) and the connecting plane arrived and we boarded between 1 and 2 am and continued on our way.