I am joining the comments here, rare for me, on the absolute debacle of the new "modern" comments. Being an educator I use colors to denote certain kinds of errors and now I cannot do this. In fact, no formatting is possible! There are a plethora of other issues that are not conducive to a positive student experience in reading and addressing comments, as well as major irritants for educators. Bottom line, I do not like this new commenting format at all! Now, I am forced to do a registry hack to restore the older version of commenting. I know this is probably going to break something else but at this point I have no other choice.
But there in lay the problem, choice has been removed. I like most of the updates to Office 365 to date and yes I did chose to have Office regularly updated. However, some updates like this which are majorly disruptive to one's work style should give the user the opportunity to not accept them or turn it off without hacking the registry. I get it that the folks at MS want a fresh look occasionally to the GUI and functionality of their products. It is one of the things I like about the product. However, users need the ability to disable updates that create problems for them. Focus on giving the user more control (choice) over their product and you will distinguish your product over the others. After all, that is what all this constant updating is about. Right?