Unification is a great word, and I think it is pretty representative of how Apple is trying to forge ahead. However, the fact remains that today, the way that iOS and OS X are converging is by OS X taking lots of cues from iOS, and not so much the other way around. Call it iOS-ification, unification, or whatever else you want.
Update 2012.02.23: Khoi Vinh, in an interview with Thomas Houston, The Verge:
I’m passionate about the Mac and what’s possible on the desktop, and I think independent Mac developers are some of the most creative minds in technology… but right now the most interesting thing happening on the desktop, by far, is Apple’s iOS-ification of OS X. They’re clearly in the process of upending a decades-old paradigm for thinking about desktop software, and whether it’s successful or not is going to be very interesting.