The alternative to "rip" is simply giving it more thought and expression - instead of reflexively announcing their death, taking the time to think about a person and try to understand their life more.
My sister has rip on her facebook page, about our brother. I haven't told her how much it bugs me, because a) we don't talk about our brother that much (only when we are alone), b) it isn't that big of a deal, c) I kind of understand what it is for: it is overwhelming to think about, and it is just a kind of punctuation mark, d) words are not her thing as much as images.
I just never liked they way "rest in peace" sounds, either. "Rest peacefully" sounds better, but I generally like adverbs. It was once a prayer or a hope or a wish, but now it sounds like a command. I don't even like the translation of the Latin to "may he rest in peace" - it sounds like an apology. T Maybe something you'd say to a kid that won't go to bed and keeps complaining from his room that he isn't tired: "REST IN PEACE DAMMIT"