The problem with canon debates, in my mind, is the difference between someone
saying something and someone
doing something.
So for instance, the Potara earrings. The Elder Kai specifically states that if you use them to fuse, the fusion is forever. But in Super, that's easily retconned by a different supreme kai saying, "Nah, it's only an hour yo". Then in GT (I know it's not canon, but I'm talking about specifically GT canon), Goku tells Pan that General Rilldo is "even stronger than Majin Buu". If we take that statement at face value, it means all of these things are also true within the Z-to-GT canon:
- Pan is at least able to fight on par with Buu as she kicks Rilldo across the face and sends him flying backward, all at base level.
- Goku, as a child unable to use his adult techniques, is now stronger than Super Buu as a regular super saiyan; do the math on how strong he is by SS4, then.
- Gohan as a regular super saiyan and not his mystic form is also now stronger than Super Buu, as he killed Rilldo in one shot. This is despite not training for over a decade.
- Uub is actually multiple times stronger than Super Buu ever was, and after fusing with Majin Buu, Baby Vegeta is still stronger, meaning Vegeta himself is stronger than Super Vegito by multiple times. Before ever attaining SS4 or SS3.
- This means that Omega Shenron, who can take on two SS4s at once and win handily, is probably stronger than Beerus.
This is all assuming that what Goku said was 100% true and not at all a bad guess.
Applying this to what's said in Super, if we write off the observations of Kefla and Vegito's perceived strength as just bad guesses (or bad writing), the power scaling all makes way more sense. So I choose to do that.