When Windows Vista was released back in 2006,
Booting up Windows Vista in a virtual machine, or even seeing it on (old) real hardware today is a very surreal experience. While XP was much loved, and 7 was well recieved, Vista has pretty much forgotten. Exploring it today, it seems like a sleek, but awkward transition between old and new. Thes are my (flawed) arguments on what I think it did right at the time. (And better than Windows 7.)
What was teased vs. what we got. At least an attempt was made.
It was never utilized to its full potential in my opinion, as the sidebar that we got in retail Vista looked nowhere as feature-rich as what was shown in Longhorn development screenshots. Microsoft didn't bother to expand on the sidebar, as it disappeared in Windows 7, leaving only the desktop gadgets. Well, due to the way they worked, Microsoft decided that they were a "security risk" and discontinued the gadgets platform altogether come Windows 8 (well, the "live tiles" sort of replaced them).
Personally I think Aero became more bland in Windows 7. Everything became more monocromatic, as evidenced by both the screenshots above these two below.
You can see that the window metrics have changed, as buttons in the top right corner were thinner in Vista. You can also observe slight difference in how the windows themselves are rendered.
The trend of redesigning everything around the stupid "ribbon" interface introduced in Office 2007 also began in Windows 7.
I don't think redesigning these bare-bones applications added much in terms of functionality or value. We were better off with the shiny reskinned Win32 GUI with proper menus.