For all intents and purposes, she's dead-dead. And she will continue to be, until proven otherwise.
Personally, I don't see the point of arguing over this. On the one hand, no one will get to convince the other. On the other, as far as the characters know, and as far as the story goes, she is dead.
Spoiler alert: Pyrrha kills Ruby. :P
I think killing Ruby (whoever is to do that) would be a bit too much, don't you think?