Has there recently been a trending popularity with scissors as weapons over swords? Why are scissors starting to displace swords as the cool weapon of choice for main heroines to wield? (Inu to Hasami wa Tsukaiyou, Kill la Kill)
Not necessarily a trend, perhaps, but it's worth noting that there's more than enough anime with swords (http://tvtropes.org/pmwiki/pmwiki.php/Main/KatanasAreJustBetter), even guns, that when a unique, less-frequent choice of weaponry comes around, it may catch the attention of a frequent anime viewer.

Example: Would Bakemonogatari episode 1 would have been more interesting if Senjougahara used a sword instead of a stapler? Probably not, unless you had some philia regarding swords.