Seems odd for such a non-technical article to latch onto a term like "micro-kernel" like it was all hot and new. OS X is built on a BSD which has it's roots in 60's and 70's OS design, just like the VMS roots of WinNT.
OS X didn't change the world by bringing some great new underlying architecture to the table. In fact, their kernel and filesystem are arguably getting long in the tooth. The value that OS X brought to the table was the fantastic Carbon and Cocoa development platforms. And they have continued to execute and iterate on these platforms, providing the "Core" series of APIs (CoreGraphics, CoreAnimation, CoreAudio, etc.) to make certain HW services more accessible.
There's very little cool stuff to be gained in the windows world by developing a new kernel from scratch. A quantum leap to something like Singularity would not solve MS's problem. The problem is the platform. What's really dead and bloated is the Win32 subsystem. The kernel doesn't need major tweaking. In fact, the NT kernel was designed from the beginning such that it could easily run the old busted Win32 subsystem alongside a new subsystem without needing to resort to expensive virtualization.
Unfortunately, the way Microsoft is built today it have a fatal organizational flaw that prevents creating the next great Windows platform. The platform/dev tools team and the OS team are in completely different business groups within the company. The platform team develops the wonderful
What Windows needs is a new subsystem/development platform to break with Win32, providing simplified, extensible *unmanaged* application development, with modern easy-to-use abstractions for hardware services such as graphics, data, audio and networking (which would probably look not entirely unlike an unmanaged counterpart to WPF/WCF/WinFS).
All your files have been destroyed (sorry). Paul.
