Dragon Ball currently has three canon anime shows, with a fourth one (Dragon Ball Daima) on the way. Unlike the other shows, Daima isn't based on a preceding manga by Akira Toriyama and is completely original. It shares this trait with a series that's now considered wholly non-canon, though this status doesn't have to remain that way.
Dragon Ball Super introduced the concept of the multiverse into the Dragon Ball franchise, with different universes having their own incarnations of Saiyans and other races. One such timeline can recreate the events of the non-canon Dragon Ball GT, which was essentially "erased" due to the events of Dragon Ball Super. Doing so can validate that controversial series while also presenting an interesting new avenue for the franchise as a whole to follow.
The Controversial Dragon Ball GT Is Not Canon
Fans Have Always Been on the Fence about Dragon Ball GT
Released in Japan in 1996, Dragon Ball GT was an anime-exclusive sequel to the events of Dragon Ball and Dragon Ball Z. The series was meant initially as something of a throwback to the former series, with Goku even reverted to a child like in the original anime. Forced to travel the galaxy to recover the Black Star Dragon Balls before the Earth is destroyed, Goku, Trunks and Goku's granddaughter Pan embarked on a grand tour full of more whimsy than pure action.
Given the epic battles seen in Dragon Ball Z, this was definitely a disappointment for a lot of fans. With the introduction of Baby and the legacy of the Tuffles, however, things which were more geared to resemble a storyline from DBZ. This all concluded with what remains perhaps the best and most powerful ending for a Dragon Ball anime, with both his now elderly granddaughter Pan and the viewers reflecting on the legacy of Goku.
Since it came out, fans have been mostly mixed about the quality of Dragon Ball GT. The one element to be universally well-received was the Super Saiyan 4 transformation, but even this hasn't saved the series as a whole from overall irrelevance. Namely due to it not directly involving Akira Toriyama or being based on a manga by him, Dragon Ball GT has been deemed as outside of true continuity for several years.
This was only cemented with the release of the Dragon Ball Super anime and manga, which did involve Toriyama and are both canon to the events of Dragon Ball Z. That show is now the true sequel to DBZ, and it introduces forms such as Super Saiyan God and Ultra Instinct. These transformations are shown without mentioning Super Saiyan 4, seemingly meaning that the form will never be truly canon. While that's disappointing for many fans to hear, there is one way in which elements of Dragon Ball GT can finally be "made canon."
The Dragon Ball Franchise Has a Multiverse
Dragon Ball Super Introduced a Multiverse into the Dragon Ball Franchise
The concept of the multiverse in the Dragon Ball franchise was theoretically introduced in the penultimate overarching saga of Dragon Ball Z. There, Future Trunks came to avert a disaster that left his timeline in ruins, and he succeeds in preventing it from happening again by saving Goku from a mysterious heart virus. Unfortunately for him, this doesn't affect his own future and change his life, thus making his timeline simply one of several different worlds in the multiverse of the series as a whole.
Such was the case whenever Future Trunks showed up again in Dragon Ball Super, with the character's life and world being vastly different from the one that Goku and his universe's version of Trunks lived through. The idea of the multiverse was cemented during the Tournament of Power, wherein fighters from different universes were pitted against each other to decide the fates of their worlds. This includes other universes with Saiyans, giving examples of universes where Goku and Vegeta weren't surviving members of the species.
At the moment, multiversal adventures are all the rage in science fiction, superhero stories and major Hollywood movies. Given how much it pulled from some of these sources in the past (Future Trunks' time-traveling storyline was inspired by the Terminator series), it would only make sense for Dragon Ball to dive even deeper into the idea. By doing so, it can look into worlds with similar concepts to what fans know, while still being distinct from the main universe.
At the same time, there may definitely be "multiverse fatigue" on the part of fans and those who consume fiction like Dragon Ball, so if the idea is used, it needs to hone in on a specific world and timeline. Future Trunks' world has already been shown off quite a bit, but the multiverse can be used to canonize an entire series.
Dragon Ball GT Can Live Again Through This Concept
Dragon Ball Super Can Establish Dragon Ball GT as a Different Universe
One of the different universes throughout the Dragon Ball multiverse can be established as the world in which Dragon Ball GT takes place. Said series will mostly be the same as the "main" universe, with the events of Dragon Ball and Dragon Ball Z still happening as fans saw them. The main difference would be that GT's storyline is the sequel series instead of Dragon Ball Super, with certain concepts such as the Machine Mutant Baby or the God of Destruction being exclusive to one universe or the other.
This universe might also feature some other interesting divergences from the mainstream continuity by way of making the Dragon Ball Z movies canon, as well. This might take some reconfiguring, but it would be a good way to make it a distinct timeline. More than ever, there's a sense of nostalgia for Dragon Ball GT, at least when it comes to certain elements. The most obvious of these is the Super Saiyan 4 transformation, and a fight between Super Saiyan God Goku from the main universe and Super Saiyan 4 Goku from the GT universe is something that many fans would love to see.
The concept of the multiverse is worth exploring for this alone, let alone the interaction between other characters from the Dragon Ball multiverse. Uub would have truly become Goku's apprentice in Dragon Ball GT, which is something that still hasn't really happened in Dragon Ball Super. Conversely, Krillin wasn't a police officer in GT and just seemed to retire in peace. Seeing this might help his mainstream counterpart feel a bit less insecure around the other Dragon Warriors.
Perhaps the most interesting difference between the two worlds, however, was seen in the final moments of Dragon Ball GT. Set long in the future, Pan and a descendant of Bulma look on as their own progeny (named after Goku and Vegeta) battle it out at the World Martial Arts tournament. Despite their having vastly diluted Saiyan blood, they can easily turn into Super Saiyans. If nothing else, this idea is something that can be explored, especially if it's exclusive to the world of GT.
Interestingly enough, the multiverse already hinted at elements from that series, with Universe 2 in the Tournament of Power still having surviving members of the Tuffles species. A possible story route is that they invade the world of GT to revive Baby and exact revenge on the Saiyans, with Z Fighters such as Goku now long gone. These are just a few of the ways in which Dragon Ball GT can be revived and redeemed, showcasing that, despite the original show's quality, it definitely had some worthwhile ideas and characters.
