Well said, JRo28 . We should be able to toggle which comment option is better.
For some use cases, I don't hate the new comments: when we have eight or ten reviewers all nitpicking wording on a two-page customer bulletin, it's nice to tag people into the doc to check things. (Tagging seemed to work fine in the old layout, though, so I'm not sure why the awful Post button was necessary.)
A lot of my work isn't like that, though. I, like a lot of people on this thread, often need to do full-doc edit sweeps and deliver a complete review on my own (no tags, no bells and whistles, just redlines and suggestions) for an audience of one initial doc creator who won't have time to review for a while. In a 200-page manual where I forget to hit Post and skip five pages up to my last comment and lose my place and my train of thought, the new comments are absolute hell and a drain on productivity.
My suspicion is that the test group only reviewed short little docs like my first use case and they didn't consult people who use the program for copy editing or legal redline markup. And in a company with the size and forced updates of Microsoft, that's an appalling oversight.