posted 04-05-2000 12:01 PM
I think it has to do with the development of the regulars and the qualities of the new characters on both sides ~When the series began there were very clearly delineated opposing sides, the Master and his minions were evil, Buffy and her friends were good. The closest that they came to moral ambiguity was Cordelia the bitca. They did have episodic villains who were given a more human slant: Amy Madison and Marcie Ross, for example, but those characters were never really associated with the regulars. Their loss did not affect them. There were no consequences to deal with.
The advent of Spike and Drusilla presented them with far more interesting villains and the show lingered on them and their relationship for longer. Since we saw more of them (and they displayed human 'love' for one another) we grew closer to them and were drawn more into their world of darkness. Other morally ambiguous villains appeared (Chris from SAR, Ampata, Billy Fordham, James Stanley) all of whom had their own, human, reasons for doing the horrible things they did. While we revile them we cannot help but begin to understand why they did what they did, and wonder whether we would be capable of the same.
The regulars were tarnished slightly as well, Halloween and The Dark Age displayed Giles' violent past, When She Was Bad gave Buffy a chance to give vent to the 'Queen C.' within.
This culminated in the Angelus story arc, another charismatic villain who increased the Spike/Dru/Angelus appeal to the writers and garnered even more screen time. At the same time the division that erupted within the Scooby Gang over the emergence of Angelus and the killing of Jenny made them all come away a little less than the paragons of virtue and a little more human that they had begun.
The increased concentration on and audience empathy with the villains was coupled with another development, the idea of consequences. The actions of the regulars began to have actual consequences for them, it actually affects them. Previously it was a case of "Evil appears, smite evil, evil goes away by the end of the episode, catch up on homework" but in Prophecy Girl Buffy has to come to terms with a portent of her own death, she has to come to terms with the fact that she is in a very dangerous profession, that death is a very real possibility and that there is no way out. Her calling as a Slayer is finally displaying all the ways in which it will affect her.
In When She Was Bad the price she paid becomes evident, it is not the case where she can die, be given CPR and then be fresh as a daisy when she wakes up the next day. No, there are consequences, nasty consequences of what she has done and what she's had done to her. Lie to Me she's forced to stake an old friend, she did the right thing in doing so but its a consequence which hits close to home. It's not a vamp who was somebody's friend, it's a vamp who was _her_ friend. The consequences of Giles' youth come back to haunt him and threaten the people he cares about in The Dark Age. Buffy's given pause for thought about her whole role as a Slayer and where it'll lead in What's My Line?, she has to deal with believing she's killed someone in Ted and, ultimately, she bears the burden of being part of the creation of Angelus and cannot help but feel responsibility for everything he does after that. The Angelus arc is the largest consequence of them all and it hits closest to her heart.
Season three has started in the same vein. The consquences of Buffy's actions in Becoming (and a surprise from Lie to Me) are explored in Anne and Dead Man's Party, there was more dissention between the Scooby Gang, real, bitter resentment because both sides had good reason for their attitude. Even Willow was pushed to the point of advocating violence to resolve the matter.
New characters have arrived: Trick, a calculated opportunist, and Faith, another Slayer, another goodie but one that lives very differently from the others.
And our regulars are older and more experienced, they've all lost some of that wide-eyed innocence with which they started this fight.
I don't think the series needs a 'heaven' to contrast against the 'hell'. We make our own heroes in the characters to match against our fears. And as we realise that they, too, are human, and that the enemy they face is not totally inhuman, the lines are blurred. The darkening is an inevitable consequence of a series that can, and usually does, takes what happens realistically.
[This message has been edited by Vox (edited 04-05-2000).]