I like the documentation and there is nothing wrong with the design per se.
But I miss the days of stupidly shiny glassy Apple buttons. Now everything is boring and flat. The icons have no detail or art to them.
If you have a mac zoom in really far on the scroll emoji on a and you'll see an easter egg which is just amazing. Every icon has so much detail in it yet also looks recognisable at small sizes. (msft employee, opinions are my own obviously.)
Only in a limited functional sense. But it looks ugly, and the actual content consists of a bunch of standard components without any clue as to how to make them work together visually, while the guidelines is just a handful of one-liners, with some bad grammar advice thrown in. It focuses on minutiae, while handwaiving the larger picture.