From the accounts I've seen, I'm surprised that BA didn't take a page out of Delta's playbook and ordered food like Pizza and so on to the airport. They could have generated some good will to compensate the incident at relatively minimal cost. At least, customers would have felt cared by BA.
IT is complex and censored stuff happens. They probably didn't spend enough on Disaster Recovery but, it's incredibly complex and there could be unforeseen issues. But it's how disasters are handled that shows the managements savviness and competence. They should have prepared for such a disaster happening after seeing it happen with Delta, they should have had a gameplan already in place for how to deal with customers, they should have a plan about how to mitigate PR issues by sending a clear message that BA is taking care of its customers (see the Delta Pizzas). They should have a way to make sure that all support staff are on the same page. That this was done so badly truly is mind boggling.
It shows that Alex Cruz is incompetent at his job and should be removed (but then we already knew that didn't we?)