I ended up holding out for the DL Elite upgrade and lucked out in both directions. When I checked in at IAD I asked the counter agent. She called over her supervisor who upgraded me into 1A on the spot. Then in MEX I asked again at the counter and was told that I was put on the list. I checked again in the lounge to make sure the counter agent had indeed waitlisted me for first. The agent indicated he had. I asked what my prospects were and he said it was booked full. I got to the gate shortly before boarding and asked the gate agent who had already upgraded me and gave me a new BP in 3B. First class was full in both directions. Based on this experience I'd be happy to fly AM again.

The flight from MEX to IAD diverted to JFK due to thunderstorms in IAD. The crew flew one leg prior and timed out so the flight was cancelled. It was a bit of a cluster at JFK, but I was second in line for hotel/reaccom and was on my way to a hotel with a voucher for breakfast 2 hours after landing. While waiting (it took an hour for an agent to show up) I called DL and got booked on the first flight of the morning from JFK to DCA. They re-booked me with no hesitation, even though my original destination was IAD. I was booked on DL.com with a DL codeshare flight so this must have helped. The pax on the original flight flew with the same plane and crew to IAD the next morning at 11AM. So I saved a couple hours. All-in-all I was really pleased with DL stepping up with the irregular ops.