For decades, soaps have killed off characters, only to bring them back months, years, sometimes decades later. The audience accepts it, for the most part. Since Voyager already had two characters from an alternate universe after the originals died (Harry and Naomi), why consider the rest of them sacrosanct?
And character death, even if the audience loved the character and is angry at the death, can be a powerful story. As an example, on Babylon 5, when Marcus gave his life for Ivanova (I assume people in general know this by now?)... I bawled through that whole thing, and his death actually meant something.
Even a current storyline on General Hospital had a character die, except not really. The audience knows the character is alive, in captivity somewhere in Europe. The character's family does not, and her husband is moving on with a new girlfriend who their daughter would love as her "new Mommy." The audience is eagerly waiting for the time when the RL actress' work commitments will allow her to return to finish out this story - I have no idea how it will be resolved, but I'm looking forward to it.
They could have done something like this on Voyager, with a several-episodes' story arc where a character is presumed dead, but is eventually brought back.