I completely agree that geo-redundancy is a hard requirement for a site as critical to the functioning of the internet as Github.
A generous reading of "We can also take steps to mitigate the negative impact of these events on our users." would include improvements of that sort.
That said, I also didn't spot any concrete proposals for geo-redundancy in the post-mortem. Perhaps that's a detail that will be figured out in a following exercise, or perhaps they really don't have any plans for GR, in which case the generous reading would be unwarranted.
