[jaen]

I'm very curious about what you consider a real "design" then?!

The Windows NT kernel had a better design than most contemporary and succeeding operating systems (including the various Unixes, Linux, BSD, plan9 etc.).

Modern kernel designs like Google's Fuchsia have more in common with NT than POSIX/Unix/Linux.

In particular, the NT object manager approach subsumes the Unix "everything is a file, well, not quite, oh... uhh.. let us slowly fix that by adding stuff like signalfd, memfd, pidfd etc. ahh hmm, these still do not exactly fit into a FS mold... ah crap, still missing a proper ptrace FS analogue" design approach that eg. Linux has taken in the last two decades.

It also had powerful primitives like eg. APCs that could be used to build higher-level kernel features elegantly.