Stuff breaks. The goal of safety engineering is as much to reduce the impact of failures as it is to reduce their frequency. Everything is about tradeoffs.
They have moved from never catch fire, in a period of a few months, to batteries they hope will not catch fire, with features to enable survivability should a battery catch fire.
If this new design is appropriate, that earlier design was engineering malpractice.
I doubt this design would be the outcome of the same Boeing design engineering effort without the get it to market time constraint. Just like when a web service goes down mysteriously and the engineers desire is to take it down and debug it and the required response is to patch it, and get her flying again. But I wouldn't term that "design" or "engineered".
This was a huge mistake, and it seemed as though they should've known.
There are additional safeguards when it comes to a jetliners powerplants. For example: The oil is never exchanged at the same time in all engines on a plane.
I fail to see, however, what this has to do with burning batteries on a plane.
A fire on a plane in flight is one of the worst imaginable scenarios, while the chances to land a plane without engine power are actually quite good. Unless you're in the middle of an ocean, that is.
A contained battery overtemp failure is not a big deal, but an uncontained battery thermal runaway is a huge safety issue. Qantas A380 was a extremely rare uncontained failure, the most serious type of malfunction. The Hudson A320 was a double engine failure, also is extremely rare. There have been incidents of maintenance SNAFU causing oil loss in all 3 engines on a DC-10, but ETOPS rules for twin aircraft prevent such incidents from maintenance causes.
An uncontrolled fire on a plane is a worst case scenario, and ironically in some cases a water ditching might actually be advisable. A contained and extinguished engine fire in one engine is not nearly as critical.
http://www.airbus.com/fileadmin/media_gallery/files/safety_l...
Which, based on the number flying regularly, means there's an in-flight failure happening somewhere in the world every few days or so.
There is a reason that every airliner of appreciable size has two engines or more.
The 787 is rated to fly up to three hours away from the nearest airport. A gliding airliner will be lucky to make a tenth of that distance.
I think the point he was trying to make is that while Boeing's actions clearly do not reduce the risk dangerous battery fire to zero, Boeing not only does not have to reduce it to zero, but really there should be no expectation that it be reduced to zero, given that we already fly accepting some sort of failure rate on the engine. This stems from the original posters implication that Boeing just used some sort of cheap hack fix so they could stem the deluge of bad PR and start making money again - with the further implication that the actions taken are a cheap hack fix since they clearly do not reduce risk to zero.
[1] http://www.airbus.com/fileadmin/media_gallery/files/safety_l...