Being a prick to your characters is the foundation of good writing. Kill your darlings an' all that. Besides, stuff can be dark as well as funny; just remember to balance everything out.

I know you don't like her very much, or at least you never used to, but the Notary is a pretty good example of this. She's a horrible, appalling, atrocious person. We've also briefly seen one of her past regenerations that indicated she wasn't always like that; something happened to make her that way. I just haven't got round to telling people what it is yet. She does have an arc revolving around going to a pretty dark place and coming out better for it, and it'll take a while to get there but that's why I'm writing the character.

To be honest with you, mate, I tend to view the actual mission portion of a PPC mission as something of an ancillary concern. We're here to laugh at the badfic, yeah, but we end up staying for the characters. We want to see their reactions to it, in a setting that allows them to do this. If we didn't, we'd be writing MST3K-style sporkings like every other collection of snarky, snobbish pseudo-comedians on the Internet. The characters and their stories are important, so if you've got a story for them, tell it. It'll be interesting! =]