I wrote Delta, mentioning the delay and the AC power unit. However, I emphasized that the primary purpose of my email was to commend the captain for the action he took and for letting the passengers know what was happening. (I had gotten his name and employee number.)
I just received a phone call from Delta, apologizing for the delay and the AC problem and thanking me for my comments about the captain. She also said that she was depositing 10,000 Sky Miles into my account.
Professionally handled by both you and Delta, I would say. Kudos.