Some people see never-existed people as moral agents, and claim that we can talk about their preferences. Generally this means their personal preference in existing versus non-existing. Formulations such "it is better for someone to have existed than not" reflect this way of thinking.
But if the preferences of never-existed are relevant, then their non-personal perferences are also relevant. Do they perfer a blue world or a pink one? Would they want us to change our political systems? Would they want us to not bring into existence some never-existent people they don't like?
It seems that those who are advocating bringing never-existent people into being in order to satisfy those people's preferences should be focusing their attention on their non-personal preferences instead. After all, we can only bring into being so many trillions of trillions of trillions; but there is no theoretical limit to the number of never-existent people whose non-personal preferences we can satisfy. Just get some reasonable measure across the preferences of never-existent people, and see if there's anything that sticks out from the mass.
It is unknown whether or not we should treat nonexistent people as moral agents (like people rather than like trees), but it's an interesting idea to consider.
If we do this, we should focus on non-personal preferences rather than personal ones, because we can satisfy infinitely more preferences that way.
This contradicts the way most people reason when they treat nonexistent people as moral agents.
However, there is a problem: we need to try and figure out the preferences of nonexistant people to see what treating them as moral agents implies.