You notice how no one almost ever wishes for anything besides resurrections or remaking a planet? Like, say, asking Shenron for a working time machine, instead of spending decades reverse engineering future Bulma's? Or I bet a bottomless bag of senzu would be useful. So the scenario is this: Goku never bumped his head, and Grandpa Gohan was forced to kill him. Despite this, the humans still managed to get together and form a team for defending Earth. You have access to kami's Shenron, with the standard ups and downs. You also have King Kai's support for knowledge dumping, and he passes the Kaio-Ken to the strongest humans. So starting with Radditz and working up to every major villains who targets or originates on Earth, can a group of competent humans with none of the PIS they're known for deal with their higher powered threats?