So anyone reading this thread has seen the whole show, right? Ok, then let's play a game.
Let's pretend that after season 2, the series was canceled. The rest of the show and the spinoff didn't happen. So Buffy has everything taken away from her: mommy, school, social life, she kills her true love to save the world, and pulls a Bruce Banner type exit into the world, modeling herself after her peer- live alone because fate demands it. We know there are still villains out there, but we know that she's there to stop them.
Wouldn't that, dramatically, be one hell of an ending? Wouldn't that make everything we've seen so far pay off to the maximum? It would be the conclusion of the saga, the ultimate hero story.
Instead, I know that pretty soon she'll somehow find herself back in high school, Angel will come back, she'll have her friends, maybe even her mommy. I'm sure there will be consequences, and I'm sure I'll enjoy the rest of the show, but just the fact that there is more lessens the value of what these last two episodes did.
But more importantly, how can vampires smoke if they don't have breath?