The big issue that the author kind of mentions is that while the kernel has all these neat features, the overlaying OS seems to use them in such a way that they’re often not effective. XP before SP1 was a security nightmare and we got lucky that blaster was not working correctly. A secure token for the processes in your session? It doesn’t really help if every process you spawn gets this token with the user being the administrator (I know this is kind of different nowadays with UAC). A very cool architecture that allows easy porting? Let’s only use it on x86. Even today, it’s big news for Windows running on ARM, which the not-by-design-portable Unices have been doing for years.

Maybe if Microsoft had allowed the kernel to be used in other operating systems - not expecting a copyleft license - the current view is that Windows Is Bad, and the NT kernel is an inseparable part of Windows. And hell, even Windows CE which did run on other devices and architectures, doesn’t use the NT kernel.

So while the design and maybe even large parts of its implementation may be good and clean, it’s Microsoft’s fault that the public perception of the NT kernel.