To be fair, I think this is true across platforms. On what platform is window management better than it was 5 years ago? Sure, Windows lacks a good way to get an overview of all open windows (such as Expose), but I honestly think Aero Snap is a killer feature for desktop use (especially because it supports the keyboard so well). When programming, I often like to have my editor and reference material side by side and Aero Snap make this literally a snap, which is great when the reference material changes frequently. Sadly, when programming, I also like to use a suite of GNU tools, which makes Windows a bit less compelling.
Although you seem to think it's gotten less good, I still think keyboard navigation remains Windows' strongest competitive advantage over OS X. It's also the only thing Windows does better than Gnome Shell which is otherwise the best desktop UI I've experienced.