Fanfic Question...

So I did 'teh crazy' and volunteered to write a Christmas fic.  I have a sort-of idea for the story but I have a long way to go to nail the whole concept down. 

Anyway, a question, what weird sort of offshoots of the Buffyverse would have happened had Xander Harris never been born?  (I'm pretty much going with the concept that Buffy would have bit it at Prophecy Girl.)  

And if you're guessing that  it's a play on "It's a Wonderful Life" you'd be right... only it's not exactly what you might think.