So Michael_Heyns and others at Microsoft - courtesy of CurtShannon nickhunn Petterfran and lcownbey you have a bunch of people telling you that the normal comment management process in normal mainstream professions cannot use a Google Docs style approach - for very good reasons.
To their examples I would add everyone who works on documents in the IT industry worldwide, everyone in government, defence, utilities, banks, retail, manufacturing, pharmaceuticals - you name it, any grown up industry uses a structured process where one person 'owns' a document, solicits comments from others, usually off-live, and then incorporates, some (but usually not all) into the draft. It such a common approach - I bet there are plenty of people inside Microsoft who work this way too - I doubt there is a single industry that you would fail to upset if you roll Modern Comments out without also providing the 'Legacy' (by which I mean sensible and functional) comments option as well.