Trek was never the kind of series that killed off main characters? Especially in the movies? What show were you watching?
Yar, Wesley, Jadzia, tons of recurring characters in DS9, Kes, and then in the movies Spock (sure he was brought back, but they didn't intend to at the time it was written, much like Janeway now), Kirk, and Data...
Main character death has always been a part of the Star Trek universe, at the very least from Wrath Of Khan forwards. Not an immensely huge part, to be sure, but definitely an important component. And Janeway is the first main character to be killed in the books... just after the books revived Trip Tucker!
The books actually have a BETTER record on this than the movies or shows do.
Neither Wesley, nor Kes were killed off.
Both individuals have now transcended the physical realm of the humanities and are off, over *there*. They might still make appearances, but they're departed mortal life.
But they can't be considered as dead since they still are out there, existing as sentient beings with the possibility to return for good.
As for Kes:http://www.geocities.com/Hollywood/Park/1964/Kesstories.html