Goku's statement for me actually has to have him know what Beerus' power actually is for it to hold any water. All he's basing it off of is Beerus finger flicking him away and movie Goku is quite a bit cocky in himself so he could be overestimating Beerus just so his bruised ego can have an easier time taking the hit. The reason why Goku is usually a reliable source for where people stand is because he's usually not biased and he can actually sense their power. Goku is quite cocky in the movie and he can't sense a shred of Beerus' strength. I already gave my piece for why he brings up the possibility of Vegetto not being viable above.Draconic wrote:I don't see how that is a point in favour of Beerus being weaker. When Goku says that fusion wouldn't work he barely saw anything of Beerus' power, so Vegito might not be as far above him, as a suppressed Beerus appears to be. We know characters don't even have to be 10% more powerful to dominate another, so if anything, the only thing contradicted are speculations made by fans regarding the power scaling of the Buu Saga.
He doesn't even have to know the power of Beerus anyway, he just has to know were Vegito stands compared to his SSJ3 form and then compare that to his own standing against Beerus (and judging by his reaction to the God power in Super, his expectations were far exceeded and then some) to be able to come up with a general idea. He didn't have to sense Beerus. Hell, we can't sense either of them, but can still grasp where they might fall based on previous events, so I am sure Goku could too.
Then, when you look at it from an out-of-universe perspective, I don't think we would get a line of dialogue thrown in there just because, especially since it appears that facts support it. I can take some guides getting some things wrong, even though they are official, but just writing stuff only to have it be untrue doesn't help with anything. And it's not even a Perfect-Cell-Solar-System case, where you could say that the character speaking the line might have been over-hyping his power, but quite the opposite, with Goku somewhat underestimating what Beerus is capable of.
I rationalize Beerus as weaker in Super because I simply refuse to believe Vegeta got anywhere close to the boost a lot of people are giving him and I buy the whole "he unlocked latent God Ki" excuse less the more I think about it. Its a lot easier to think of them making the stronger guy weaker so the heroes look better in comparison. And apparently Goku in the Super continuity who's not any stronger than his movie counterpart before attaining God is already making Beerus use 100% of or something real close of his full power power where as the movie version remains completely outclassed for the duration of the film.
Sora Saiyan The thing with that is, Vegetto can still be better than God with Goku rationalizing why he simply avoids using him. 1) he knows Vegeta would be reluctant to say the least to use the fusion Bulma slap or no and 2) he'd be stuck as Vegetto permanently after simply fusing into him for the sake of a single battle. God might not give Goku as big of a boost as Vegetto would, however, it also opens up doors for Goku to improve his power radically without needing to rely on Vegeta or fusion. This obviously works better for movie Goku who actually objects to needing other peoples strength while Super Goku is, as you said, to hyped with himself to even bother putting some thought into it.
