I kind of have the impression that Kripke pays a little too much attention to the more vocal end of fandom. Which unfortunately, is that when it was announced two new female characters were being added there were a great many (presumably) female viewers shouting a lot of "Oh, Noe! Ick gurls!" That's something that didn't so much decrease, as create a sort of schizophrenic quality to reading response posts in the blogosphere and going from, "Analysis of gender/race issues," to "Die, pejorative die!" posts. It's only recently that the first type seemed to reach numerical parity with the later.

Which isn't one way or the other with regards to the show itself, but there are times I think the vocal osmotic effect of fandom isn't always to a benefit of stories that are written in the t.v. hothouse.