EEngr
If Boeing does discover the cause and goes back to the drawing board with an updated design, the FAA (and others) may give them a clean sheet of paper, so to speak, on battery reliability. Eventually, the battery box could go.
No the battery box will stay it is part of the RTCA standard for LiIon - even the new Cessna Citation has one.
Some people will remain unconvinced, however there was a large task force of industry experts most from outside Boeing who identified all the faults that could cause problems and fixes were put in for those.
Boeing wins
nothing by trying to get out of testing or by not making a complete fix,. There only needs to be a minor problem of any type and all the naysayers here will shouting about it; another 787
battery problem would be a company challenging event.