It seems like you could write ghouls in a way so as to not ruin them. If they can be in Necropolis surley they can be elsewhere too, just exceptionally rare. Even to the point that you'd be both famous and infamous for it. Maybe only have around 3 in a game. One of them could even be an old one from Necropolis.
I'd really like to see how ghouls who managed to have children before turning deal with seeing generations of their family be born, have a childhood, mature, have children of their own, grow old, and die. Would they just seppuku their way out, or find a way to live with it and possibly be a genuine family elder centuries old and with a lot of insight? Seems like that would possibly position a family very well if the ghoul ancestor was smart and had connections. A type of royal family fallout style?
Maybe mix some ancestral issues in a la Dune?
Seems like ghouls who survive that long would have to be smart, filling the role of thinktank, or resaercher for a settlement. Ugly, frail and very rare maybe, but very potent in other ways.
That's how I'd write ghouls at least.