To respond to that particular argument, which I don't see how substantiates the point that morality according to Eliezer's meta-ethics could be void.
When you're considering what a human mind would conclude upon considering certain new arguments, you're thinking of ways to improve it. A natural heuristic is to add opportunity for reflection, but obviously exposing one to "unbalanced" argument can lead a human mind anywhere. So you suggest a heuristic of looking for areas of "coherence" in conclusions reached upon exploration of different ways of reflecting.
But this "coherence" is also merely a heuristic. What you want is to improve the mind in the right way, not in coherent way, or balanced way. So you let the mind reflect on strategies for exposing itself to more reflection, and then on strategies for reflecting on reflecting on strategies for getting more reflection, and so on, in any way deemed appropriate by the current implementation. There's probably no escaping this unguided stage, for the most right guide available is the agent itself (unfortunately).
What you end up with won't have opportunity to "regret" past mistakes, for every regret is recognition of an error, and any error can be corrected (for the most part). What's wrong with "incoherent" future growth? Does lack of coherence indicate a particular error, something not done right? If it does, that could be corrected. If it doesn't, everything is fine.
(By the way, this argument could potentially place advanced human rationality and human understanding of decision theory and meta-ethics directly on track to a FAI, with the only way of making a FAI using a human (upload) group self-improvement.)
I believe that in Eliezer's meta-ethics, both the extrapolation procedure and the coherence property are to be given fixed logical definitions as part of the meta-ethics, and are not just "heuristics" to be freely chosen by the subject being extrapolated. You seem to be describing your own ideas, which are perhaps similar enough to Eliezer's to be said to fall under his general approach, but I don't think can be said to be Eliezer's meta-ethics.
making a FAI using a human (upload) group self-improvement
Seems like a reasonable idea, but again, almost surely not what Eliezer intended.
Barring a major collapse of human civilization (due to nuclear war, asteroid impact, etc.), many experts expect the intelligence explosion Singularity to occur within 50-200 years.
That fact means that many philosophical problems, about which philosophers have argued for millennia, are suddenly very urgent.
Those concerned with the fate of the galaxy must say to the philosophers: "Too slow! Stop screwing around with transcendental ethics and qualitative epistemologies! Start thinking with the precision of an AI researcher and solve these problems!"
If a near-future AI will determine the fate of the galaxy, we need to figure out what values we ought to give it. Should it ensure animal welfare? Is growing the human population a good thing?
But those are questions of applied ethics. More fundamental are the questions about which normative ethics to give the AI: How would the AI decide if animal welfare or large human populations were good? What rulebook should it use to answer novel moral questions that arise in the future?
But even more fundamental are the questions of meta-ethics. What do moral terms mean? Do moral facts exist? What justifies one normative rulebook over the other?
The answers to these meta-ethical questions will determine the answers to the questions of normative ethics, which, if we are successful in planning the intelligence explosion, will determine the fate of the galaxy.
Eliezer Yudkowsky has put forward one meta-ethical theory, which informs his plan for Friendly AI: Coherent Extrapolated Volition. But what if that meta-ethical theory is wrong? The galaxy is at stake.
Princeton philosopher Richard Chappell worries about how Eliezer's meta-ethical theory depends on rigid designation, which in this context may amount to something like a semantic "trick." Previously and independently, an Oxford philosopher expressed the same worry to me in private.
Eliezer's theory also employs something like the method of reflective equilibrium, about which there are many grave concerns from Eliezer's fellow naturalists, including Richard Brandt, Richard Hare, Robert Cummins, Stephen Stich, and others.
My point is not to beat up on Eliezer's meta-ethical views. I don't even know if they're wrong. Eliezer is wickedly smart. He is highly trained in the skills of overcoming biases and properly proportioning beliefs to the evidence. He thinks with the precision of an AI researcher. In my opinion, that gives him large advantages over most philosophers. When Eliezer states and defends a particular view, I take that as significant Bayesian evidence for reforming my beliefs.
Rather, my point is that we need lots of smart people working on these meta-ethical questions. We need to solve these problems, and quickly. The universe will not wait for the pace of traditional philosophy to catch up.