Adding another 200 lbs doesn't seem significant.
Adding 200lbs to the OEW of any commercial airliner, even one as large as the 787, is hugely significant.
Not so much for the impact on fuel burn, though it doesn't help, but for the effect on payload and therefore revenue potential over the life of the aircraft.
OTOH, if that's the price that has to be paid to get the type back in the air (and I suspect it will be) then that's what will happen.