I disagree with that, but that's just my opinion. I'm not a Snape fan.

And while I guess you could say Harry's cloak as an exception, the Horcruxes are actually mentioned from book two...just not by name. Even still. Rather by name in book six (and really allusions to Horcruxes are made throughout the entire book), than the very last book. Introducing the catalyst for the final quest in the penultimate book was fine. Introducing a whole new thing in the last book was something I didn't care for.