Excellent point. It comes when you don't create a character but a plot device. Most Star Trek relatives are simply plot devices.
 
A Star Trek relative that wasn't a plot device is Sarek. Such a well drawn and acted character, Sarek even made the transition into a later series and the movies. He lived.
	
		
			
		
		
	
				
			A Star Trek relative that wasn't a plot device is Sarek. Such a well drawn and acted character, Sarek even made the transition into a later series and the movies. He lived.
				

 I suppose it was a good thing we got the one single look at her and that was all.