Just to add another disappointment I had with the game, we never get to play through the many training moments the characters went through in the series. I really thought we would be able to do Kaio's training, gravity room x100 on the way to Namek, extensive sparring with other characters, and maybe even the afterlife (the closest we get is Vegeta's training room, which is fine on its own, but I feel more could have been done with it instead of just fighting past enemies on a generic wasteland). The story skips ahead and just feeds you EXP, giving us little control over our character levels. Sure, the side quests do give substantial bonuses despite not being required, but they're all pretty simple to do and your overall progress wont be much different from other people if they do the same. You play as Gohan and the others throughout the Saiyan and Namek arcs for a long while, constantly leveling them up after each battle, and then Goku comes out nowhere and is now by far your strongest playable character despite not having much gameplay with him previously. My point is that I want my progress to feel earned and not be spoon fed just so I can compete with the constant escalation of power.
As for the side quests themselves, while I enjoy them for providing new stories and development for characters, there is valid criticism in saying that the vast majority of them simply revolve around fighting robots or aliens and collecting things with no variation to it.