I mean, yes and no. I still find death to carry significance if the writers use it effectively. My personal favorite episode "Balance of Terror" makes the horror of war and death quite weighty, even though these characters we have no familiarity with, beyond just meeting them. It carries weight because it impacts the characters.Because death in fiction is utterly meaningless. It isn't real. It just ends storylines.
Same with Data, Jadzia and David.
It's all in the writing. It can be used well, or it can be used poorly. But it is hardly meaningless.