Lets assume each of those prosecutors sends >1 person to prison. Then imprisoning said prosecutors would likely result in fewer prisoners.

-I guess the key here is "too little evidence". The courts would need to establish that the prosecutor either withheld evidence, knowing it would strengthen his case or at the very least through gross negligence caused evidence to not be presented to the court.

Considering the at times terrible information flow in my office (engineering Co.), I do not think it neither feasible nor fair to lock up prosecutors for any mishap - though I expect the possibility of prison time would work wonders to improve information flow!