Moral standards in general can improve irregardless of the number of people involved. Besides, one could argue that having more slaves is outweighed by having much more non-slaves living good lives. In regard to cryonics: all else being equal I’d favor to be reanimated in a world with low slave to non-slave ratios if I preferred the probability of my becoming a slave to be as low as possible.
Moral standards in general can improve irregardless of the number of people involved. Besides, one could argue that having more slaves is outweighed by having much more non-slaves living good lives. In regard to cryonics: all else being equal I’d favor to be reanimated in a world with low slave to non-slave ratios if I preferred the probability of my becoming a slave to be as low as possible.