I remember Vista & 7 both had the Aero Glass themes, a new light blue theme that replaced the Luna themes from XP & the Classic theme. Sure a lot of color schemes & things like cool looking cursors went away, but you could easily copy most of them from older versions. Only limit I can think of is that the blue theme that replaced Luna (And is technically based off of it) sucks.

8 is the version that basically nuked customization with only the new flat theme replacing everything.

Also, fun fact, the blue theme from Vista & the classic themes both do technically exist in 8 & up, but they are hidden & seeing them usually means something is broken.

As for Linux theming, look at DEs other than GNOME, most are still pretty customizable

Well, it is at least in part how many linux distros configure Grub, it can be set up to boot the last selected OS, which I think should be the default... I changed it on all of my dual boot systems, though I haven't been using Windows all that much lately, so it hasn't been all that big of a deal for me.

I just wish that Windows hadn't changed the default update config to restart no matter which option is selected, since it makes that situation soooo much more annoying.