The bit where Shiling bops a thug on the head and Hsu tosses them over the railings is broadly comedic; but more, I feel, for the routine they've settled into more than Shiling's broom. I think that if her weapon of choice was supposed to be a big joke, they would have had other characters questioning her effectiveness, or had her scenes play out with comical sound effects or "BAM!" graphics, or something— there's certainly many a JRPG that play their improbable weapons for joke fodder— but there are two separate times in the game Shiling fights with a broom, and both times she's portrayed as competent and reasonably effective. I like that.