We have a Vegeta Fanboy in the house (SS4FlameAlchemist).
That aside, I laughed hard because Vegetas role as a "bad ass" was very short lived post Frieza saga. He was merely a plot device to provide fodder for filler episodes inbetween the real battles.
While I do agree that this joke fits Krillen a lot better, anyone who has seen the entire Z series can't argue that this is for the most part true, and the embellishment is what makes it funny.
All my 5 are belong to this.