You can include notes and author feedback on individual content blocks.
Click the title of the article
Navigate to the Admin area and click on the title of an article. This will open a preview of the article.

Click the notes icon
A note icon appears to the right of each content block. open the menu and click Add note
Write your note > click Add a note
If you type @ then you will have the option of calling out a specific Admin or Editor.

See which content blocks have notes

Editor receives an email
If you call out an Admin or Editor, then he/she will receive an email with the note you write, as well as a link to the note.

I have a feature request.
As an editor, can I see a list of comments other editors have made on the web dashboard somehow instead of just getting an email?
Also, there needs to be a better way to do peer-reviews of content that Editors have authored. What I would request is a different user type altogether that can write notes on different content but doesn't have access to edit it.