Well, the batteries may not be off the hook as much as the Japanese safety investigators, as quoted here, believe :
Japan: Over-charging preceded ANA 787 battery malfunction
Now the NTSB says there was no overvoltage to the batteries:
NTSB rules out excess battery voltage in Boston 787 incident | Reuters
So there is as yet no obvious simple cause for the failures and hence no quick end to the grounding. This is not good for either Boeing or its customers, because it also suggests that better monitoring of the batteries may not help.
An emergency replacement of the battery seems inevitable. Could Boeing just switch to the certified unit from the 777 and offset the performance shortfalls with process changes? Restarting the APU does not seem to be too demanding a task.