When it works correctly, absolutely. The problem is that often times it doesn't lead to bigger fish but more fish of equal or lesser size since the system often values quantity over quality when it comes to felony convictions.

You'll see this a lot of times when they catch a mid-level dealer. The dealer will roll on the street-level dealers instead of their supplier since it yields dozens of easy felony drug convictions instead of one really difficult case that could eat a ton of resources and still be lost.

I read some comment that in the post Gates era the Los Angeles police stopped going after bigger fish and just started straight out prosecuting little fish. Which probably worked better.

The problem with the previous way was criminals would turn 'states evidence' and either finger other little fish, or littler fish, innocent people[1], or big fish already in jail. Then they'd get released and go back to committing crimes. Not to mention the police protecting criminals that made a career out of turning in people as a form of protection.

[1] This happened to friends of mine.

Which would still not be an argument against the existence of plea bargaining, as the OP was advocating.

Looking back I don't see that the OP mentioned the other big issue with plea bargaining: when innocent people plead guilty because it's often the best choice. My bad for adding my own context onto it.

Decent writeup:

http://www.nybooks.com/articles/2014/11/20/why-innocent-peop...

tl;dr: the current system incentivizes defendants (especially poor ones) to plead guilty regardless of innocence. This is caused by a combination of prosecutors/judges trying to be "tough on crime", overloaded public defenders, excessive bail, mandatory minimums and several other things.

I don't think plea bargaining is absolutely unfixable or evil but I also don't think it's a well-functioning part of the system as-is. I believe this is one of those cases where removing an option might be better for the justice system as a whole.

And (as I often argue here[1]) that's still a mispurposed argument when used against plea bargaining per se, rather than against the forces that give prosecutors so much disproportionate leverage that people take them.

It's not even a case where removing an option can have good global effects; if you remove plea bargaining but change nothing else, all that accomplishes is that disadvantaged people get railroaded harder, and choke up the courts even longer as they play out their lopsided trials.

[1] https://news.ycombinator.com/item?id=12465613