Put me down as a long time many-worlder who doesn't see how it makes average utilitarianism more attractive.

It seems to me that MWI poses challenges for both average utilitarianism and sum utilitarianism. For sum utilitarianism, why bother to bring more potential people into existence in this branch, if those people are living in many other branches already?

But I wonder if Eliezer has considered that MWI plus average utilitarianism seems to imply that we don't need to worry about certain types of existential risk. If some fraction of the future worlds that we're responsible for gets wiped out, that wouldn't lower the average utility, unless for some reason the fraction that gets wiped out would otherwise have had an average utility that's higher than the average of the surviving branches. Assuming that's not the case, the conclusion follows that we don't need to worry about these risks, which seems pretty counterintuitive.