Arguably the larger issue is that law enforcement has so much power to force people into plea agreements instead of trials. The reason grand juries are so prosecutor-friendly is that you're supposed to have a right to a jury trial where the facts can be tested in an adversarial setting in front of people who are supposed to be skeptical of what you're being accused of. In theory, that might be reasonable.
In practice, something like 95% of criminal cases don't go to trial, and many trials don't involve a jury. Some of that is because the defendant is clearly guilty -- legitimate crimes do happen, and sometimes you get indisputable video evidence. But some of it is because the law and public perception is so tilted towards cops and prosecutors that arguably innocent defendants are bullied into plea agreements when in a perfect system they would get their day in court.
Arguably the larger issue is that law enforcement has so much power to force people into plea agreements instead of trials. The reason grand juries are so prosecutor-friendly is that you're supposed to have a right to a jury trial where the facts can be tested in an adversarial setting in front of people who are supposed to be skeptical of what you're being accused of. In theory, that might be reasonable.
In practice, something like 95% of criminal cases don't go to trial, and many trials don't involve a jury. Some of that is because the defendant is clearly guilty -- legitimate crimes do happen, and sometimes you get indisputable video evidence. But some of it is because the law and public perception is so tilted towards cops and prosecutors that arguably innocent defendants are bullied into plea agreements when in a perfect system they would get their day in court.