Well...  That was about the most tragic thing I've ever read.  Perhaps
that's overstating, but Soun and Genma killed Ranma and Nabiki.  To be
sure they were replaced by people who were probably happier but the old
ones are gone.  

C'mon...realistically do you think that Nabiki would become a devout 
long-term practitioner of the martial arts just because she fell in love 
with a martial artist?  And if Ranma fell in love with Nabiki you know 
that the first thing he'd be likely to do is ask her why she hasn't
been extorting money from him like the money grubbing opportunist 
she really is.