After years of non-canonical depictions, Broly was officially introduced to Dragon Ball's main continuity with the 2018 anime film Dragon Ball Super: Broly. The Legendary Super Saiyan proved to be even more formidable than before, forcing Goku and Vegeta to fuse into Super Saiyan Blue Gogeta to take him down.
As the long-running story continues in the manga, Vegeta has grown significantly stronger since his last skirmish with Broly. This has renewed the debate about how the Saiyan Prince would fare in a potential rematch with the Legendary Super Saiyan.
Following the battle against Broly, Goku and Vegeta underwent rigorous training to take on the magical villain Moro, a warrior capable of draining the life force of those around him to augment his strength. To combat this devastating ability, Goku trained with the angel Merus to master the Ultra Instinct transformation while Vegeta underwent grueling training on the planet Yardrat.
This training made Vegeta stronger, but it also gave him him the ability to perform Instant Transmission and further manipulate energy with a technique known as Forced Spirit Fission. This move draws energy similar to Goku's Spirit Bomb but can manipulate fusions and restore stolen energy. As the Saiyans prepared to face a new adversary in Granolah, Beerus refers to Goku and Vegeta as the strongest warriors in the known universe.
Broly, however, wasn't mentioned at all. A rematch between Broly and Vegeta is something of a given -- the Legendary Super Saiyan was spared and returned to the faraway planet Vampa with some newfound friends. While Goku and Broly formed a tentative friendship once the latter calmed down, his potential to lose control and unleash his destructive power remains an omnipresent possibility. Even against Super Saiyan Blue Gogeta, Broly gave his composite opponent a worthy challenge, with the clash being powerful enough to shatter across dimensions. That said, Beerus' omission of Broly suggests that the Legendary Super Saiyan is now the universe's third most powerful warrior at best.
The question remains how Ultra Instinct Goku would fare against Broly, especially now that the Saiyan hero has gained greater mastery over the combat transformation. While Vegeta remains unable to achieve the Ultra Instinct transformation for himself, he clearly possesses enough power even just in his Super Saiyan Blue state to close the gap to Goku -- as evidenced with his role during the final battle against Moro.
As the showdown reached its climax, Vegeta restored Goku's energy to make the Ultra Instinct transformation. He has such an impressive command over raw energy that he could even separate Piccolo from his fusions to Nail and Kami if he wanted. This suggests all the immense energy within Broly could similarly be controlled by the Saiyan Prince.
Super Saiyan Blue Vegeta couldn't even slow Broly down in their previous skirmish, forcing him to fuse with Goku to save the day. Now, after his intense training regimen on Yardrat and development of the Forced Spirit Fission technique, the Saiyan Prince could take all the immense combat power at Broly's disposal and turn it against him.
Vegeta has come a long way from the cocky Saiyan Prince who arrived on Earth searching for the Dragon Balls. With his villainous ways now far behind him in Dragon Ball Super, the Super Saiyan God appears to have finally surpassed the Legendary Super Saiyan.