As pages of negative comments indicate, Modern Comments is a disaster for many entire professions --for my work as an educator, it's very negatively impacting my work flow by adding extra steps (consequently time) and removing several options in legacy comments.
Autotext is no longer supported in a comment, which adds time as I must copy/paste from a separate document to insert frequently used comments.
The extra steps for inserting and editing each comment (usually many in each paper) slow down my work on HUNDREDS of papers a semester.
The addition of a separate comment column takes up valuable screen space and requires a reduction of document view that hampers readability and increases the likelihood of eye strain.
CUSTOMERS should have control and choice -- everyone's needs are not the same. Microsoft can easily make this an individual choice.