The forgotten older brother of Dragon Ball’s hero, Goku, should have a bigger role in Dragon Ball Super. Raditz served under Lord Frieza since he was a young Saiyan, traveling from planet to planet, conquering them for the evil cosmic overlord. Raditz’s origin is very similar to Vegeta’s, having served together and being roughly the same age, but time has treated Vegeta much more kindly than Raditz, something that should be remedied.
Raditz made his first appearance in Dragon Ball Chapter 195: The Mysterious Warrior From Space by Akira Toriyama. Upon his arrival, Raditz kidnapped Goku’s son, Gohan, in an attempt to pressure his brother into joining him and his wicked mission across the cosmos. The Saiyan’s story didn’t last long, however, as he was killed off after Goku used all of his might to hold down the villain as Piccolo delivered a deadly blow, killing Goku along with Raditz. While Raditz begged for his life, he found solace in the idea that his compatriots would use Earth’s Dragon Balls to bring him back to life, though if the promise of resurrection was off the table, Raditz would not have died a warrior's death.
Raditz was not brought back as he had hoped though, but with the continuation of the Dragon Ball lore with Dragon Ball Super, he could easily return and become a main character along with his brother and Vegeta. A prime example of an early DBZ villain making a comeback is the resurrection of Frieza who, in Super, was able to achieve a power level fans had never expected from the character. The same could be brought to Raditz, though given his reaction to the possibility of death, he may not be much of an asset to the current Z-Fighters as Frieza proved himself to be.
Raditz showed cowardice before Piccolo killed him, and even before when Goku had him by the tail and weakened the villain. Both instances showed that Raditz pleads for his life in dire situations rather than being unafraid at the prospect of death. For a Saiyan to reach a higher level of power, they have to train so hard that they come to the brink of death, then either die or unlock a new, more powerful form eventually leading them to Super Saiyan. Unless Raditz overcame his fear of death upon his hypothetical return, he would go the way of Yamcha and be stuck as a mid level powerhouse of a bygone era.
While Raditz died early in the Dragon Ball lore and hasn’t yet made any sort of a return, Dragon Ball Super hasn’t completely forgotten about the character. During the Granolah Saga there is a flashback to Goku’s father, Bardock, and his contribution (or lack thereof) in the Cerealian genocide on Granolah’s home world. Raditz’s portion of the flashback was small, showing the Saiyan as a child playing with a bug, though it does give some insight into his character. The Saiyan’s minor appearance shows that there is some good in him and that perhaps he was merely corrupted by Frieza as Vegeta once was but is worthy of redemption. Plus, Raditz is Goku’s brother so it is reasonable to assume he has the capability of unlocking an incredibly high power level if he were to build up the courage to push himself. Raditz could be recreated into a character that his original self wouldn’t recognize and add another champion to the Z-Fighter squad and reunite him with his brother, Goku, and old fighting companion, Vegeta, in future Dragon Ball stories.