Den Beste talks about what wusses the Jedi are and how Vegeta could have easily kicked butt agains the Jedi en masse. Well yeah, but so what? Making such comparisons just rewards authors who assign fantastic and implausible powers to their characters. It's like competing on who can name the biggest number. "My character can blow up whole planets!" "Only Earth-sized planets. My character can blow up Jovian sized planets!". I note in passing that one of the most enduring and popular fictons, Middle Earth, doesn't seem to have any characters with this kind of power level. Even Sauron is quite constrained in his ability compared to a DragonBallZ character.
But that's not the real problem. Where these overpowered characters come from is partly from this kind of competition, but it's generally internal. In order to keep reader interest without being really inventive, an author can simply up-power the next villian. First a villian threatens a person, then a village, then a city, then a nation, then a planet ... At some point it becomes clear that there is no "back-story" but simply arbitrary decisions that are purely plot based. Star Trek suffered from this - how exactly did all of these super powered races / beings co-exist? Did the Q ever have problems with the Telosians? Note that the problems arise because of the galaxy spanning powers assigned to opponents to make them "interesting". However, judging by the Klingons and even the Dominion, it's possible to have interesting opponents who are powerful but not implausible. DragonBallZ managed to escape the worst effects because each opponent lasted dozens of episodes. The worst effects are seen in super hero comics where a new opponent can show up every episode. The ultimate extreme is The Authority where the heros cruise around in a reality plane hopping space craft powered by an entire universe (no mere star sized fusion reactor for these folk!). An author can write himself into a vicious circle where a up-powered villian is needed to challenge the new found powers of the hero needed to vanquish the previous up-powered villian...
Of course, one way around these problems is to throw away continuity, as was done for Richie Rich where any amazing invention needed as a plot device was simply ignored in other episodes. You can even get away with that in main stream content for adult viewers, such as The Simpsons, where any damage to Springfield was simply elided for the next episode.
The fact that a Jedi blast is roughly equivalent to a small artillery shell and not a world destroying blast like Vegeta's Ki attack is a meaningless comparison. Are sword fights in movies no longer of interest because of Harrison Ford's scene in Raiders of the Lost Ark? The powers of the heros should be part of the warp and weft of the ficton. Comparing them across fictons is meaningless and more is in no way instrinsically better.