This series tackles what would happen if Vegeta's self destruction in the Buu Saga was permanent. Muchlike how Piccolo describes Vegeta's experience in Otherworld, it would involve his Soul being cleansed thus never returning for all the bad deeds he comitted. And without the threat of Majin Buu, as instead Goku opts to deal with the threat himself (or befriending his opponent), BoG plays out very differently. With less than the amount of Saiyan's of pure hearts needed for the ritual, Goku has to instead fight on pure instincts. And so the rest of DBS follows on.