Kwang Sun Kim
Kwang was an Olympic Gold Medalist Amateur boxer who wouldn't turn professional until the advanced age of 26. After only 5 professional bouts, he took on arguably the best Light Flyweight on the planet in Humberto Gonzalez and was actually winning the fight fairly comfortably until he was stopped in the 12th round on a Technical Knockout.
As a result of this good showing against one of the premiere fighters in the world, Kwang was offered the opportunity to fight Michael Carbajal in America. Just like he had done against Chiquita, Kwang turned in an impressive showing and was winning the fight going into the 7th round where he was caught with a left hook which sent Kwang reeling to the ground. He climbed up off the canvas but Steele was forced to stop the fight once it became obviously that Kwang's legs had completely gone.
Kwang retired with a record of 6-2. Let's assume for a second that he had seen out the 12th round against Humberto Gonzalez and became the WBC Light Flyweight champion of the world. We could have seen Kwang build up a respectable title reign in his native Korea before losing a competitive fight with Michael Carbajal. Perhaps he should have turned professional sooner.