AD published in 2011
Given that the AD related to the 8-10 compressor stages was published in 2011, hasn't there been plenty of time in which to redesign and fit replacement parts to eliminate the problem across the fleet?
Sure, doing so would have been expensive. However, if this had turned into a fatal accident, avoidance of that expense might now look negligent.
This raises questions as to how long a known and potentially (and in this case very nearly) fatal defect should be allowed to persist regardless of the perceived likelihood.
Now that this has happened, it is also worth questioning whether the industry has its priorities right. GE/Boeing were not in favour of the FAA's inspection regime, presumably because of the cost and inconvenience to their customers. Four years down the line the expense could have been billions in fines and compensation had the BA crew not succeeded in conducting a textbook evacuation. This sounds like penny pinching on a large scale, and the consequences might have been the lives of passengers.
Writing as a passenger, that doesn't look great to me. What would have looked great was a proactive replacement program in excess of the FAA's requirement starting 4 years ago. Writing as an engineer it is yet another example of big businesses failing to acknowledge and act on "unlikely" risks with a catastrophic outcome merely for the sake of small amounts of short term money.
GE/Boeing have just had a lucky escape; they may well end up carrying the can for this one. Thanks to the BA crew the can isn't so big. If the NTSB finds that it was indeed the 8-10 compressor that failed then that won't exactly help GE/Boeing in their sales campaigns...