Society is worse off if Blackstone's Ratio is not followed. The harm caused by a criminal act is not equivalent to the harm caused by a wrongful conviction: the former is unambiguously illegitimate whereas the latter is legitimate and supported by the government in the name of the people. Society has many ways of mitigating the effects of crime: we have insurance, victim support groups, etc. But if you're wrongly convicted, you have nothing. After all, you're a "criminal" not a victim and that's how you'll always be remembered.
The exact number of guilty people in the ratio doesn't matter. No one can agree on it, and it's impossible to quantify the harm anyways. It's really more about the idea of fair trials and the presumption of innocence, which is a handbrake against tyranny. It's a warning that the fear of letting guilty people go must not be used to justify diminishing the presumption of innocence. This is why Blackstone's Ratio was supported by people like Benjamin Franklin and John Adams whereas a "reverse" Blackstone's Ratio (better to let X innocent people suffer than let one guilty person escape) was embraced by such delightful people as Otto von Bismarck, Feliks Dzerzhinsky (founder of the Soviet secret police), and Pol Pot.
The exact number of guilty people in the ratio doesn't matter. No one can agree on it, and it's impossible to quantify the harm anyways. It's really more about the idea of fair trials and the presumption of innocence, which is a handbrake against tyranny. It's a warning that the fear of letting guilty people go must not be used to justify diminishing the presumption of innocence. This is why Blackstone's Ratio was supported by people like Benjamin Franklin and John Adams whereas a "reverse" Blackstone's Ratio (better to let X innocent people suffer than let one guilty person escape) was embraced by such delightful people as Otto von Bismarck, Feliks Dzerzhinsky (founder of the Soviet secret police), and Pol Pot.