Others have pointed out that 1. Anya's speech to Buffy in Empty Places is a good description of privilege and 2. Treating slayerness as a privilege doesn't really make sense, especially given the expected lifespan of a slayer. It occurred to me that there is another problem with treating slayerness as a privilege: Spike's speech in Touched. If Buffy is "privileged", Spike is essentially saying she deserves to be privileged. That has a lot of squicky implications. So I think I will continue to see slayerness as not a privilege.
Also: I just re-watched The Replacement. Lately I've been seeing people say, without a source, that Xander is Joss Whedon's self-insert. I have a hard time believing that a man who wrote an entire Firefly episode based on the writings of Jean-Paul Sartre would have as his avatar a construction worker who is insecure about never having gone to college. I'm not trying to put down Xander - you don't need to go to college and have a white collar job to be smart and successful. But he is very different from Joss Whedon.