There are generally considered to be two schools of thought for punishing criminals. Retributivism is the belief that prosecutors must cause criminals to receive their "just deserts". That is, justice is served when criminals get what they deserve. Utilitarianism is the belief that prosecutors must cause criminals to be punished because it is useful to society. That is, justice is served when a punishment makes society a better place to live.
Utilitarian justifications for criminal punishment fall into 4 categories.
General Deterrence - Punishments should be calibrated to incentivize lawful behavior among the general public. This is why high-profile cases often result in more strict punishments than low-profile cases.
Specific Deterrence - Punishments should be calibrated to prevent the criminal from acting unlawfully in the future. This is why "Three Strike Laws" were enacted.
Separation - Punishments should ensure that law abiding citizens are not at risk of being the victim of crime. This is why prison is a popular form of punishment.
Equiy/Cost - Punishments should be calibrated so as to not be more costly than the crime it was intended to prevent and punish. This is why jail time can sometimes be avoided if the defendant pays a criminal fine.
It is very difficult for me to answer the question that you presented, but I would say that a retributivist prosecutor would say that it is wrong for a person to receive more punishment than they are due. However, a utilitarian prosecutor with equity/cost in mind may point out that the only way to be cost-efficient with the resources available is to convince most defendants to plead guilty.
Why do you believe it is important to punish criminals? Do you think that prosecutors are correct when they say the only way to be cost efficient is to convince most defendants to plead guilty? Based on your beliefs, should a prosecutor charge defendants so as to "scare" them into a guilty plea? Is this as true for violent crimes as it is for non-violent crimes? Is this true for intentional crimes versus "accidents"?