Indeed, whether AU avoids the RC in practice depends on your beliefs about the average welfare in the universe. In fact, average utilitarianism reduces to critical-level utilitarianism with the critical level being the average utility, in a large enough world (in uncertainty-free cases).
Personally, I find the worst part of AU to be the possibility that, if the average welfare is already negative, adding bad lives to the world can make things better, and this is what rules it out for me.
Indeed, whether AU avoids the RC in practice depends on your beliefs about the average welfare in the universe. In fact, average utilitarianism reduces to critical-level utilitarianism with the critical level being the average utility, in a large enough world (in uncertainty-free cases).
Personally, I find the worst part of AU to be the possibility that, if the average welfare is already negative, adding bad lives to the world can make things better, and this is what rules it out for me.