I'd like to nudge in one thing: option flexibility. I'm still downloading and about to try it out; but I hope that the setting does allow the user to tweak everything they can tweak and not hide options away for the sake of hiding things. My personal thing, but it's shared with many, is that flexibility can lead to a personally complete design.
Flexibility is definitely something we try to be opinionated about. We don't offer a lot of easy GUI customization out of the box, but you'll find that there's quite a bit hidden beneath the surface or is easy to code up yourself.
If you're really interested in a completely customizable and hand-tailored OS, I'd honestly suggest you look into something like ArchLinux or Gentoo[2]. Both platforms have made available most of our applications and components, so you can pick and choose to build the desktop you personally want :)
Pantheon's Arch Linux support is not finished - I'm pretty sure you can't run Pantheon on it. However, on Gentoo I'm sure you can.
Besides that, we do offer some customization, you just have to use dconf-editor to change the configuration keys and not a GUI for several things. And there's also "elementary Tweak" which adds even more configuration.
