I recently finished a long Spangel all-human AU. It was written several years ago but I just got around to reading it. I enjoyed it, but there was one thing that realllllly bugged me - the complete and total absence of Buffy Summers. Almost every other Buffyverse character showed up, down to Gwen Raiden (or however you spell her name) who showed up in two, maybe 3, Angel episodes. It would have been so easy to include her - Joyce was in it and all it would have taken was a throw-away line about "her daughter Buffy who was away at college" and I would have been perfectly happy. Instead, I spent a lot of the story wondering "when was Buffy going to show up." I don't see how you can write a fic with every other Buffyverse character, but ignore the existence of Buffy herself!