Launch could become more confident. In a new setting like Planet 16, she would be forced to adapt quickly. This would make her rely on her own instincts more, thus growing in confidence.
Well, perhaps in the fanfiction, Launch could be transported to a parallel universe on Planet 16. In this universe, the rules of Dragon Ball are a bit different. She might find herself with new abilities or facing different versions of her friends and foes. For example, Vegeta could be a king in this universe and Launch has to figure out how to deal with his different personality while also trying to find a way back to her own universe.
Goku is, without a doubt, one of the most popular. His constant pursuit of strength and his ability to overcome seemingly impossible odds make him a favorite for fanfiction writers. They can create all kinds of new adventures for him, like facing off against cosmic threats even greater than what he's encountered in the shows.
Goku's understanding of different universes and races could be deepened in fanfiction. Since Dragon Ball Super introduced the multiverse concept, fanfiction could explore how Goku interacts with and learns from beings from other universes, making him more worldly and less naive in some ways.
One interesting fan theory is about the potential hidden powers of some minor characters. For example, some think that Yajirobe might have a secret super form that was never revealed in the original series. It's just a fun idea that fans like to explore in fanfiction.
One of the interesting power - ups could be his Ultra Instinct form. In fanfiction, it might be further enhanced, like having different levels that are not shown in the original. For example, he could have an Ultra Instinct - Kaioken combination which would be extremely powerful.
Perhaps a fanfiction where Vados senses a new threat approaching the universe. She enlists Goku to help her find a way to stop it. Along the way, they encounter strange new races and powers. Goku's simple but powerful approach to fighting combined with Vados' wisdom would make for an interesting dynamic as they search for a solution to this impending doom.
A fanfiction might explore Good Broly's relationship with the other Saiyans on Earth. Maybe he starts training with the younger Saiyans like Gohan and Trunks. He could teach them about the raw power of the Saiyans from his own experiences. This would lead to some interesting training sessions and a new bond forming between Broly and the rest of the Z - fighters.
One great Dragon Ball and Naruto fanfiction is 'The Ninja Saiyan'. It combines the unique powers of the Saiyans from Dragon Ball with the ninja skills in Naruto. The story follows a character who has the blood of both a Saiyan and a ninja, and his journey to master both powers and protect his world from new threats.
In general, it depends on your perspective. Some might find it inappropriate as it can be a rather odd and perhaps not in - keeping with the traditional values of the Dragon Ball Z series. However, in the world of fanfiction, there is a wide range of tastes, and as long as it doesn't cross into truly offensive or unethical territory, some may consider it a creative, if strange, exploration of the characters.