I suspect that the vast majority of criticisms I read are from people who rarely, if ever, use Windows 8. Consider the "start button problem" everyone who actually uses Windows 8 has (by logical necessity) solved the problem...and whatever the problem existed, supposing one did, is gone from Windows 8.1 - a free upgrade released last summer.

8.1 also successfully addressed the legitimate criticism regarding better modal integration of Metro and Desktop metaphors.

Most of the criticism of Windows 8 is generated in an echo chamber with a tradition of anti-Microsoft tribalism born in the dawn of the public commercial internet. Windows 8 introduces the replacement for a 40 year old WIMP metaphor and many people don't want change.

This seems to be the biggest Problem IMHO. All I hear is,how people are trying to get the old look back. (How to add Startmenu button? How to launch directly to Desktop? ...)

Power users who also disproportionately post on forums about things they dislike seem to dislike it but I'd bet there are a lot of normal users quietly getting on with it.