I love the buffy universe on the games I played, and I thought the rulebook (actual paper copy or something) that I thumbed through was hilarious, campy, just fun and just right). I would play the hell out of a Buffy game!
But I fucking HATE the TV show. Battlestar just put me to sleep (another universe that I enjoy exploring through RP and /reading/ about on a wiki or whatever, but don't like the TV series, except for the Lorne Green stupid-ass crazy version of my childhood), but Buffy actually triggered dislike in me for some reason.
That's the thing I love about MUSHing. Come to think of it, I didn't enjoy Robert Jordan's books and I'm neutral on the old and next-oldest Star Wars shit (eps 1-6), but I LOVED those MUSHes, and I am like the only person I know who really enjoyed the WEG sourcebooks and rulebooks for Star Wars. I have super fond memories of TTing Star Wars. 🙂
Super fixated on "correctness" people will always find something to pick at. They'll fight about "correctness" even if you follow the rulebook (just ask anyone who's played a Fading Suns games about endless and tedious to all but themselves historical knowledge wang waving on chan with people arguing and criticizing one another about how they play their fictional "house" because their PhD in 6 million different kinds of RL ancient history tells them that's not how it would be at all!)
So I say, figure out the parameters of the lore/world that YOU as staff/gamerunners enjoy, make sure people know what they are and what will be within the "Scope of the game" (whether that's restrictions, alternative history, whatevs) and just let people who would whine self-select out and/or create their own place (and you stay away if what they create would make you whine!) or boot them if they're too disruptive!