Bardock is in no way a “good Saiyan”. He’s still a loyal soldier, he still goes on his missions, takes part in the wholesale slaughter of people. Gine may not have a stomach for combat or much skill at it, but she too is loyal to the Empire she serves. (Her addition was also pleasant. :D)
Goku also still arrives on Earth with a very aggressive streak that IS still only removed by that blow to the head. You’ll recall, both of them gave birth to Raditz as well, and he was anything but “good”. Personality is not something that inherently carries over, though certain traits can… which may also explain Gohan’s distaste for fighting despite his Saiyan blood and having a mother who was also a martial artist. Something he inherited from his grandmother.
I liked it though simply because it removed the sorta-ridiculous need for Bardock to mysteriously be given the ability to see the future via a blow to the back of his head. It gave use a peek at Saiyan society and how they go about raising children, keeping them in an incubator to sustain and strengthen them until they’re ready.
It also explains why Goku, Vegeta, Raditz, etc. would be the only ones left out there and no word ever got back to Planet Vegeta: Freeza realistically could not, would not, waste time sending hit squads out after every Saiyan on a mission and risk a survivor. He ordered them all back home for a meeting and THEN nuked them, with Goku only surviving off his father’s gut instinct, and the others because they defied their orders to return.
To me, these bits of information make a lot more sense AND are more interesting. Also makes Goku and Freeza’s encounter seem a lot more chance than destiny, and thus Freeza even more culpable in his own demise.
That’s why I like it as much as I do, and why I think I’ll like this upcoming movie more than not. There’s a good deal of fanservice, sure, but there’s also some established universe expansion going on for the first real time In a DB movie.Â