Natural look is dated? No, the natural look is reality. The flat look, with no depth or shadows or translucency is like... 1990's, Windows 95, 16-color dated. That's how windows 8 looks to me.
The Aero Glass theme is the most modern, most beautiful theme I've ever seen on any OS ever. Even the wild KDE Desktop themes and effects are cheesy compared to Aero Glass. Glass looked sophisticated compared to the others, especially with the parallax of
the glare effects when moving windows.
I'm a developer, and I've designed game engines. I know all about performance. Switching to a pre-rendered desktop (a.k.a. desktop composition) was a very smart and long-awaited move (Apple had it for a decade prior, based on my experience viewing their smooth
window animation when I was in Jr. High (I'm almost 30 now). This composition including the glass blend shader effects can easily be offloaded to the GPU, so this imaginary performance hit is ridiculous. If there were inefficiencies, they could have been
improved. Finally, there was no reason to not make it available. There is no reason the start screen couldn't have been a giant full-screen glass panel.
The Windows 8 start menu was old-news to me, considering I invented it back in 2003 when I was still an undergrad. In my graduate work, I formalized the design with "scenario-based design" methodology and presented it to my class, as well as to Lockheed Martin
in 2007 (who incidentally wanted to patent it, but I wouldn't let them, explaining that I had already shown it to many people and wanted it to be free). It came complete with a full-screen display of icons (based on what was in your quicklaunch folder) that
could be expanded in width to display additional information about each shortcut. I used the F8 key with a global hook to activate it (since I couldn't hook the Windows key in Win XP), and to start a search, all you had to do was start typing. After each
letter typed, it would refilter the matching icons, by looking for the letter sequence anywhere with the shortcut name, filename, or shortcut description, so that typing "IM" would match "AIM" as well as "GIMP". After each re-filtering, the non-matching icons
would smoothly fade out in place, and the remaining icons would smoothly animate to regroup, in order, in the center of the display. I have this all documented and graded long before Windows Vista even arrived, and even presented it at Lockheed Martin in
2007 as I said. So as far as I'm concerned, Windows 8's start screen is nice, but it actually botches the idea I came up with long before. If you read my scenario-based design specification (a formal specification from Authors at PSU which I adopted for
my design), it details exactly why every aspect of this full-screen tile system with morphing "live" icons is most efficient, as well as more suitable for a touch display. But again, Windows 8 got the details wrong, so it's not that great or usable. For
example, in my system, the icons remained in the same places so that your spacial memory could allow you to quickly touch the same spot every time at a given resolution. It supported scrolling as well as page up/down, so you could skip pages and still touch
in the same spot from memory. Anyway, I'm glad they at least moved in that (obvious) direction, but I've demonstrated and reasoned that it could be done much better. Nice try.
Bottom line, removing a feature does not count as a performance improvement. How about removing the entire OS, that would free up a lot of processor cycles! No. The Glass effect was important. The blurring was functional and aesthetically pleasing and calming.
I have zero interest in Windows 8 at this point.