I like rockin' used as an admiring term, havta say. As for whom, I have a strong suspicion it was imposed by those tight-assed 17th-century grammarians who tried to turn English into a branch of Latin.
No, I like a living language, but I like it precise. Or when it's not precise, at least colourful.
I particularly like new slang formations.
There's a great book called The Hacker's Dictionary (or maybe Hackers') about the new language used by hackers - that term used in its original sense of excellent coders.