This is a form of negative utilitarianism, and inherits the major problems with that theory (such as its endorsement of destroying the universe to stop all the frustrated preferences going on it in it right now)

I'm pretty sure that most forms of negative preference utilitarianism are "timeless." Once a strong "terminal value" type preference is created it counts as always existing, forever. If you destroy the universe the frustrated preferences will still be there, even harder to satisfy than before.

It might, but it would be one that was outweighed by the larger number of preference-satisfactions to be gained from doing so, just like the disutility of torturing someone for 50 years is outweighed by the utility of avoiding 3^^^3 dust-speck incidents (for utilitarian utility functions).

To get around this I employ a sort of "selective negative utilitarianism." To put it bluntly, I count the creation of people with the sort of complex humane values I appreciate to be positive, for the most part,* but consider creating creatures with radically simpler values (or modifying existing complex creatures into them) to count as a negative.

This results in a sort of two-tier system, where I'm basically a preference utilitarian for regular ethics, and an ideal utilitarian for population ethics. In situations where the population is fixed I value all preferences fairly equally.** But when adding new people, or changing people's preferences, I consider it bad to add people who don't have preferences for morally valuable ideals like Truth , Freedom, Justice, etc.

*Of course, I also reject the Repugnant Conclusion. So I also consider adding complex creatures to be negative if it pushes the world in the direction of the RC.

**One exception is that I don't value extremely sadistic preferences at all. I'd rescue the person who is about to be tortured in the Thousand Sadist' Problem.