The incidents that led to the grounding of the B787 look suspiciously like the potential dangers of adopting L/I batteries that were spelt out by FAA in Special Certification Conditions at Federal Register, Volume 72 Issue 196 (Thursday, October 11, 2007)
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And in addition to all that the batteries are meant to solely power the aircraft in the event of a total failure of all other electrical sources - which does happen now and again, even on a four (not two) engine 747.
Not sure I want to see all those protections kicking in when the plane is just a few miles short of the threshold in an emergency situation. Or when the APU needs to be started up in the air.
Did the engineers foresee such circumstances?