The issue is not that MS is imposing changes on the users but that those changes are not advancements over the previous system. As others have said, Metro and forced full-screen on mobile displays indeed makes sense but it's not an improvement over the Explorer shell for non-touch devices.

The MS tablets failed because they tried to force a non-touch OS onto touch devices. Now they are forcing a touch OS onto non-touch devices as if making the mistake in the other direction will be the magic bean.

Change the UI in ways that are an improvement over past interfaces. Deliver more of those under the hood advancements they've been promising then pulling for each OS version. Why is my OS not using journalled de-duplicated file system already? Deliver more non-UI advancements (win7 backup is a very welcome improvement over previous).

Honestly, I'd love to welcome Win8. This is not a matter of fear of change but of the OS introducing things that hinder the user because MS doesn't want to provide a mobile and non-mobile UI choice.