The Euthyphro debate shows the limitations of the system. I can think of at least half a dozen arguments off the top of my head that would blow his out of the water, but there's no way to bring most of them up, and most of my attempts either get laughed off or are interpreted as me trying to insult him. (No, I'm not just saying that Euthyphro in specific is flawed, I'm saying EVERYONE who tries to interpret the gods is flawed, and so unless the gods come down to give their judgement themselves we can't rely on them.)