I personally do not think the opinion makes sense as it is premised on the idea thet there can be no punishment or retaliation in a give and take negotiation
At least if they had to announce their charge to the public they's have to really think they could prove it and face down the appearance of overcharging.
If we imagine a grand jury to be a constraint on overcharging, and jury nullification a constraint on overcharging, then popular response to overcharging, by whatever standard the 'public' perception of overcharging is, will be at least some constraint of the prosecution.
hayes if i’m not mistaken also highlights the problem with mandatory minimum sentences and taking the power of sentencing discretion away from judges and giving it to the prosecutor
concept of equality in bargaining power seems a joke: the prosecutor risks losing a case by reason of overcharging. the defendant risks prison or death penalty for going to trial.