If Goku never lost his tail, his powers and abilities might have developed differently. Maybe he would have retained some primal monkey-like traits that could have given him unique advantages or disadvantages in battles.
If Goku never lost his tail, storylines could have taken a completely different turn. Maybe it would have unlocked hidden powers or abilities that weren't otherwise accessible. It could have also led to new conflicts and challenges within the Dragon Ball universe that we never saw in the original canon.
The most interesting aspect is probably the new power - ups. Since he still has his tail, there could be new forms related to it. Maybe a combination of his normal Super Saiyan forms and his ape - like abilities. It's exciting to think about how this would look in battles.
Well, if Goku didn't lose his memory, his relationships with his friends and family could have developed differently. Maybe he'd have fewer conflicts or approach problems with a clearer mind.
Well, in the original story, Goku's loss of his tail was a significant event. But in this fanfiction, with him never losing his tail, it might mean he has different powers or abilities. Maybe he can still transform into a giant ape at will, which could change the way he battles. For example, in a fight against a powerful enemy, instead of using his normal Super Saiyan forms, he could use his ape form to overpower the foe in a more brute - force way.
Perhaps in this fanfiction, Goku remembers all his past battles vividly. This could lead to him having unique strategies against old foes. For example, when facing Frieza again, he recalls every single move Frieza made during their previous encounters and is able to counter them with ease, making the fight much more one - sided in his favor.
Obviously, Goku is the central character. His unaltered memory shapes the story.
Another possibility is that a new form of training or power - up in the fanfiction is related to the tail. So Goku is made to keep it for his growth and development as a fighter.
Well, in a lot of fanfictions, the story might rewrite the rules of the Dragon Ball universe. So Goku could keep his tail simply because the author wants to explore different storylines with a tailed Goku. Maybe the author thinks it adds more to his character's appearance and abilities, like being able to use it as an extra limb in combat or for balance during his super - fast flying.
One possible plot could be that Goku's power development takes a completely different path. Without the head injury that altered his original Saiyan nature in the official story, he might be more in tune with his Saiyan instincts from the start. This could lead to him being more aggressive in his battles and perhaps having a different moral code when it comes to fighting. He may not have the same innocent and somewhat naive view of the world that he had in the original story, which was partly shaped by his head injury.
One interesting plot could be that Goku's tail gives him a new power. Since it's always been a unique part of him, perhaps it allows him to communicate with a certain race of creatures that are only attuned to the energy his tail emits. Another plot could be that he has to protect his tail from an enemy who wants to use it for some dark magic. The enemy believes that Goku's tail holds the key to unlocking a powerful spell, so Goku has to constantly be on guard while still going about his normal adventures.
For Goku's relationship with the other Z - Fighters, it could be a mixed bag. Some, like Piccolo, might see the tail as a potential weakness that enemies could target. So he might be constantly on Goku to protect it. On the other hand, Yamcha might be jealous that Goku has this unique feature that makes him stand out even more. However, overall, Goku's tail could also be a unifying factor. It could remind them all of Goku's alien origin and make them more aware of the vastness of the universe and the different species within it, which could strengthen their bond as a group.