I'm not so sure about that. After all, the system has a need or at least can put to work the aberrations (like Makishima) if it can catch them alive, to perfect itself further. So a person like Kogami is in fact an enemy of the system. He's not really a relic of the past either because a field execution has never been the style of any proper justice system. I'd say he's a reminder of the imperfection of the system, but not a solution. A person like Akane (who actually has a working detective's brain) is the solution as long as the system continues to exist.
But then again, Kogami might have been just a one-hit-wonder, so maybe as long as the pray wouldn't be Makishima, he wouldn't actually try to be the prosecutor, the judge, and the executioner all in one, so you could still be correct.