Originally posted by Wei Phoenix
If he could destroy a sun, (he can't) then where would he go? He would kill himself by doing that and Superman would just go back to Metropolis.
Metropolis on Earth, eh? Well, that'll be fun for him.
And Vegeta could fire off a ki blast, get in the Saiyan space pod, and go wherever he wanted...most likely a planet with a red giant/brown dwarf instead of a yellow star.
Firstly, as your so keen to point out usually Kento, GT isn't canon. Secondly, there's no way that was Goku SSJ4 at his full power- he didn't take very long to power up, and he'd just spent the last 30 mins being beaten nearly to death by Bebi Vegeta. Thirdly, just because they DIDN'T destroy the sun doesn't mean they CAN'T destroy the sun- in the case of Broly, most of the power is presumably being counteracted by Broly, for one thing, and it's only the power of a few SSJ1's and a Namekian, all of whom were a moderately injured by this point.
Also, the problem with Superman is he's got too much canon- it's not consistent across the whole thing. The explanation given that the yellow sun is the source of his power explains (sort of) why he can survive flying through the sun- but it means that a sufficiently powerful ki blast- like a Spirit Bomb- should be able to destroy him if a) they destroy the sun or b) they can power it up to be more intense than the sun.
As for the reason that planets aren't destroyed on a regular basis from the Android Saga onwards- it's because the Z fighters aren't idiots, and would sort of prefer not to blow up the planet, taking themselves and their families with it.
For an example of an attack that does use more than enough energy to destroy the planet, Vegeta's Final Flash- Trunks and Krillen are certain that the attack will destroy the planet if it hits the surface, but Vegeta focuses and directs it to curve away from the planet after hitting Cell- it goes off into space out of sight.
A Final Flash from EoZ SSJ2 Vegeta should be more than enough to destroy the sun- more likely that than the Kamehameha because it's more focused and controlled.