Yes its a bad thing. With that said I have 2 characters I refuse to kill off. If their death is needed to further the story then the death is going to be something in which makes the readers and the characters within the story believe he is dead. I most likely wouldn't bring him or her back in the same story. But if for some reason I were to write a differnet story and want to bring him or her back... then I can. Of course I will probably piss off a bunch of people. But just because I love my characters doesn't mean I wont have them beaten to an inch of their life.
Oh, one thing worse than characters being killed off is characters who are killed off and then return later. It makes death seem trivial and cheap, like in Dungeons & Dragons.
Eh, only if it happens all the time. If it's instead an extremely rare one-time occurence, that requires considerable preparation, effort and/or luck, then you get the direct opposite effect: the ressurection becomes something incredibly valuable and important. (What I like to think of as the Chrono Trigger clause.) Plus, consider that one might actually want death to be trivial and cheap. It depends on the story, really.
Yeah I know. Of course oddly I never actually plan on doing this. I like to leave my characters open for further stories if possible. Especially the two I have in mind when I said this. Though I never plan on literaly bringing back someone from the dead. Unless its because of a Necromancer and he or she wants to raise an army of zombies.