This is what I wanted to say but couldn't say it like this.I just read Ars' review...yes all of it...and it seems to me that there are so many paradigm shifts to user interaction that this really should have been called OS XI. Although most of the superficial look to the UI remains...albeit a bit muted.
It's my assumption that Apple retained the much of the familiar look as a way to transition users into a more radical shift with less angst...like ripping off a bandaid slowly. I expect those more superficial elements to be changed next go around.
I also echo John's position that the skeuomorphic designs of iCal and Contacts add little value and even reduce value when some of the implied functionality doesn't exist, as well as by adding visual noise & silliness. I hope this isn't Apple's direction.