No one complained about Base Vegetto vs Buuhan back then, and are only retroactively complaining about it now
Even the Elder Kai hinted about a "rival bonus" back in DBZ
Hell, even before that we had Gotenks vs Buu when the SS toddlers are weak as hell (Goten only just learning how to fly). And Potara is supposed to be much stronger than the Fusion Dance.
Fusion is, and has always been, broken.