By all means, we should allow defendants to simply confess and plead guilty if they wish.
But we should not reward them for doing so. Never should a person be presented with a choice between a certain lesser punishment, or a fair trail and a potential greater punishment. That's the "bargain" in "plea bargain," and it's completely reprehensible.
You say, "few defendants would utter that phrase without there being either a benefit to owning up, or an extra penalty for not doing so." That's exactly how it is! A plea bargain isn't just, "we both know you did it, so just confess and let's skip all the lawyers and stuff." It's always, "We both know you did it, so confess and we'll let you out early. If you insist on taking this to trial then we will throw the book at you." A lot of innocent people will take the plea when faced with that choice.
Not every crime needs to go to trial, but every accused criminal needs to have the right to a trial without being punished for exercising that right. If you remove the punishment then you'll no longer have plea bargains, just pleas.
In my view a vital aspect of the trial is to provide necessary public oversight of the police and courts.
I think that a partial measure towards reforming plea bargains would be to require the police to present their evidence for the court to review before entry of a plea. This creates a public record that somebody could investigate in the future. There could also be a provision that if exculptatory evidence is revealed in the future, the plea can be rescinded.
But we should not reward them for doing so. Never should a person be presented with a choice between a certain lesser punishment, or a fair trail and a potential greater punishment. That's the "bargain" in "plea bargain," and it's completely reprehensible.
You say, "few defendants would utter that phrase without there being either a benefit to owning up, or an extra penalty for not doing so." That's exactly how it is! A plea bargain isn't just, "we both know you did it, so just confess and let's skip all the lawyers and stuff." It's always, "We both know you did it, so confess and we'll let you out early. If you insist on taking this to trial then we will throw the book at you." A lot of innocent people will take the plea when faced with that choice.
Not every crime needs to go to trial, but every accused criminal needs to have the right to a trial without being punished for exercising that right. If you remove the punishment then you'll no longer have plea bargains, just pleas.