NT upto 4 was beautiful when it was released in my opinion. It was a "serious" "workstation" operating system. Supporting multiple platforms.

The ability to run different "operating systems" was neat. The graphics stack was all in user space.

The biggest hope was a selling WindowsNT with Alpha CPUs to the Defense department if memory serves. (Which is why the POSIX parts were added) That never happened.

NT4 was not made to be the best OS for games.

After that Microsoft has cut a lot of neat parts out and bastardized the clean separation between the kernels and user space in order to make the OS faster.

I wish they had branched it "Windows Home" and "Windows Workstation"

It would be a lot of work I guess. They do have Windows Service but I think that it has undergone the same changes.