'Monsters' as PCs

I'm less than keen on the notion of allowing monsters as player characters in any game I run. Or rather, I'm reluctant to allow any members of antagonist races as PCs - I have no difficulty with vampire PCs in Vampire, but would have a problem in Werewolf, for instance.

The reason is that allowing a 'normal' member of the antagonist race into the party invariably changes the nature of the enemy race. You can't have debates about whether orcs are inherently evil or not if you've got an orc in the party. Moreover, having an orc in the party makes running adventures featuring orcs as enemies more difficult - what's to stop the party from just negotiating? And will the orc PC feel comfortable about killing his kin?

You can, of course, get round this by making the PC a unique exception to the nature of his race. So, he's the only good drow, the only Borg to have been freed from assimilation, and the only vampire with a soul. The problem there is that this doesn't make the PC unique - it makes him a walking cliche. We've seen this plot done to death now, thanks to Drizzt, Seven, and Angel. It's not fresh and exciting; it's annoying and trite.

The other problem with the 'unique exception' character is that you then have to consider the possibility of redeeming the rest of the race in the same way.

Why not simply use the soul restoration ritual, writ large, to restore the souls of all vampires? If a totally untrained witch is capable of performing the ritual on one vampire, couldn't the same witch, once powerful enough to destroy the world if she wants, cure all vampires the same way? Hell, even if she can't get them all, why not do as many as possible?

If one Borg can be broken from the collective, why can't the rest be saved? (In fact, if Borg can be saved, the end of Voyager becomes much more interesting. By wiping out the Collective in the way that she does, Janeway perpetrates an act of terrible mass murder simply to get her crew home more quickly. Nice to see that she has a fine sense of morals.)