I have not used Windows to do any real work in 20 years, so I have no idea how good or bad it is nowadays. Last time I used it I used LiteStep.
I have used various window managers on Linux, Solaris, and BSD over the years, and different ones push you into different workflows, and moving between them can involve an adjustment period. But none of them were as anti-keyboard as MacOS is. And you always had the option of switching.
Regarding rotation, it would get confused and resize windows as if they were in the other rotation, menus would open in the wrong places, and if the menubar had so much content that it would not fit (mostly on displays in portrait mode), the results would be inconsistent and sometimes unusable.