K'Ehleyr's death plays the "Women in refrigerators" trope the absolute "T". Her death is solely meant to motivate the male character into action and it's used even further to give us another father/son bonding moment, because we haven't had enough of that in this one season alone, haven't we?
Using a one- or two-appearance character to motivate action on the part of a main character! I am shocked and appalled!
1-In TNG, most the of guest stars didn't have more than one appearance, male or female.
2-Welcome in 1990! Saving or avenging the beloved, the children ore the best friend was a pretty common motivation for an action hero.