The benefits of hindsight are amazing.
For instance you can't now argue that Boeing should have given the batteries an extra 100kg weight allowance because that would make very little performance difference for the simple reason that if you did that you'd have to allow every other manufactured component some extra weight as well - calls for heavier batteries are able to be made now because you have strong reasons to suspect a different but heavier battery type wouldn't have led to this issue.
Similarly with outsourcing. It is done all the time, presuming that proper quality accreditation was put in place for suppliers then it is standard commercial practice. If Boeing had to do everything in house they would probably be bankrupt due to all the extra staff they would have had to employ (on USA rates and conditions etc) and capital equipment spent on manufacturing machinery and other capital heavy startup items which would be more costly than having that load spread around the industry. You could argue they should have batteries in house, but only with hindsight.
And so it goes on.
The 787 will be a cracker airplane, no question about that. It's just a matter of being honest about issues and fixing them.