Have multiple users edit email at the same time

PLEASE consider adding a comments feature in email previews to ease the workflow for teams who collaborate on campaigns. There is an incredible amount of time wasted communicating necessary edits, asking questions about content, and scanning a campaign numerous times that could be solved with the addition of a comments feature. (I'm thinking of how such features within Google Docs or Airtable assets review are tremendous time-savers that add value to their products).  

Thank you for your consideration!