Alex says: I’m surprised that some one as distinguished as your self sees this as a tidy reversal on the theists arguments.
Well I admit the God of Eth is as it stands a thought experiment designed simply to provide a challenge - to give believers a jolt, if you like. There are innumerable moves that might be made to defend God, and it is hard to anticipate them all in one short article (well, it's impossible).
Theists may conclude the argument must therefore be weak and inconclusive. But that would a mistake I think. After all, there are innumerable moves that might be made to defend belief in an Evil God, too, far more than I mentioned (try coming up with your own - it's fun). Yet it remains blindingly obvious to anyone with eyes to see that there is no such being. The question is: why isn't the same true of the good God hypothesis?
Alex then says. The all evil God experiment unravels for this very simple reason: Evil is the perversion of an already extant good.
I am aware of this move, of course. It's broadly Augustinian. But this also looks reversible, doesn't it? I can say "Good is just the absence or perversion (from evil God's point of view) of an extant evil." Make up some examples for yourself: Good sex is just evil sex plus consent and respect; good pain is just evil pain that also provides useful knowledge.
Seems to me that maybe the only reason it looks to you like evil things are merely a perversion of extant goods is that you have your good-God glasses on. Put my evil-God glasses on and everything switches. What grounds do you have for thinking you're wearing the right glasses?
In fact, there may be an asymmetry here that you could exploit, but you need to do much more work to bring it out.
But in any case, even if you are right about this asymmetry, you objection still assumes a great deal. You say:
God is necessarily not subject to any standard.
But actually, a standard of good and evil independent of God's judgement is something even many Christians accept (because they know about Plato's famous Euthyphro dilemma - ask e.g. Leibniz). And once we acknowledge such an independent standard, it is then open to evil God to approve of what is independently evil in exactly the same way as it is open to good God to approve of what is independently good.
So, not withstanding the possible reversibility of "evil is a perversion of good", your objection also assumes something that even many Christians, for good reason, reject.
Having said that, it was a very interesting try. Maybe it could be developed further...