how exactly would you distinguish the universe in which we live in from the universe in which human moral change was determined by something like a random walk through value space? Now naturally a random walk through value space dosen't sound like something to which you are willing to outsource future moral and value development. But then why is unknown process X that happens to make you feel sort of good, because you like what its done so far, something which inspires so much confidence that you'd like a godlike AI to emulate (quite closely) its output?

What do you mean by 'value space' (any human values or desires?) and 'moral change' (generally desirable human values?)? Also, a godlike AI is like playing with infinities when inserted in your moral calculus; a godlike AI leading to horrible consequences per your morality doesn't show that your morality was fully flawed (maybe there was a tiny loophole no human would try or be capable of exploiting). And I think you discount the possibility that there are many moral solutions like there are many solutions to chess (this is especially important when noting the impact of culture on values).