So, I played through the new substories and they're okay. Each of them is successive to the previous one, essentially making it closer to a mini-arc rather than unconnected quests.
First one has Galu searching for supplies for a Freeza Force soldier from Planet Temp who's using them to buy time to get the Dragon Balls to revive Freeza. Eventually, he decides to come clean to Goku due to his kind heart (and the soldier's love of Earth women making him not want the planet to be destroyed), with Goku instead just reviving Freeza and his soldiers as sparring partners as with previous side quests. Seems that Freeza will just be alive and hanging around should they adapt the ToP. One thing I like about this substory is that the Planet Temp soldier is working for Freeza as part of a contract he has with the planet with them recommending his services, further fleshing out the business side of the Freeza Force that isn't explored often.
Second substory is Present Trunks having trained in secret
troll) and wanting to fight against his dad, thus being far more in line with his Boo Arc characterisation than Super has been. Jheese interrupts the training for a grudge match against Vegeta, gets stomped and runs off in shame. It's suggested Trunks indeed made huge gains when Vegeta made it apparent he wasn't pulling his punches during their sparring. Jheese shows up again with Zarbon, Dodoria and Cui to help him out...which obviously makes zero difference and he just ends up blasting off again Team Rocket style. Not much to this substory beyond at least not pushing the kids to the background as Super does and the exchange between Vegeta and Trunks towards the end being pretty funny.
The third substory is just Goku and Vegeta finding Zarbon and Dodoria, fighting them and discovering Freeza's been going through a new training regime to become far stronger. You fight him and it's made apparent he hasn't improved that much in so little time. At the end, he decides he'll be a regular sparring partner to Goku until he's capable of defeating him, which unlocks a new gimmick of the mode in which you fight Freeza with him becoming progressively stronger each time you win and offering sacred waters as a reward, essentially being an amped up version of what the Whis battles were in the previous DLC but without bonus requirements, as well as some similarities to the "Challenge the God of Destruction" battles since you can't use healing items.
