I haven't had to write in a news style too often, but headlines (from AP guidelines at least) are meant to stand entirely on their own and without context.

While I agree that language can and should change, the use of hyperbole, slang, or cliches in a headline can negatively impact the clarity of the headline, which is most important.

Does something like decimate or carnage have two widely accepted meanings now? Then as an editor, I would caution against their use in a headline. Something like "Hundreds sickened in suspected mass food poisoning at New Zealand university" seems fine and is without clickbait.