I'm coming in from a different fandom, wherein a HUGE amount of the current 'fic is about resurrecting characters. I think a lot of it has to do with the quality of the show and the need to fix what's broken with the canon. If a character died and it was right for the character and the series, people won't be as likely to jump on the "Bring back Joyce, you bastards!" bandwagon. If it was handled badly, if it was gratuitous, then you'll see a lot more demand for a resurrection, and a lot more fic to scratch that itch. (The only Buffy fic I ever wrote brought back Tara. It was for a ficathon, though, so it was by request. *shrug*)